diff --git a/ChangeLog b/ChangeLog
index b6de1a1d94f..5377a690e1f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -56,6 +56,7 @@ For users:
 - New: [ task #1060 ] Register fields localtax(1|2)_type into details tables.
 - New: [ task #923 ] Localtax support for ODT templates. 
 - New: [ task #90 ] Barcode search.
+- New: Add hidden option MAIN_VAT_DEFAULT_IF_AUTODETECT_FAILS.
 
 For translators:
 - Qual: Normalized sort order of all languages files with english reference files.
diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index d8bdb60d8a4..3296a879523 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -3370,12 +3370,14 @@ class Form
         	// Comme ils sont tries par ordre croissant, dernier = plus eleve = taux courant
         	if ($defaulttx < 0 || dol_strlen($defaulttx) == 0)
         	{
-        		$defaulttx = $this->cache_vatrates[$num-1]['txtva'];
+        		if (empty($conf->global->MAIN_VAT_DEFAULT_IF_AUTODETECT_FAILS)) $defaulttx = $this->cache_vatrates[$num-1]['txtva'];
+        		else $defaulttx=$conf->global->MAIN_VAT_DEFAULT_IF_AUTODETECT_FAILS;
         	}
 
         	// Disabled if seller is not subject to VAT
         	$disabled=false; $title='';
-        	if (is_object($societe_vendeuse) && $societe_vendeuse->id == $mysoc->id && $societe_vendeuse->tva_assuj == "0") {
+        	if (is_object($societe_vendeuse) && $societe_vendeuse->id == $mysoc->id && $societe_vendeuse->tva_assuj == "0") 
+        	{
         		$title=' title="'.$langs->trans('VATIsNotUsed').'"';
         		$disabled=true;
         	}
diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index 7b21c9ca20c..78e9ec1f2a8 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -2908,17 +2908,15 @@ function getLocalTaxesFromRate($vatrate, $local, $thirdparty)
  *
  *  @param	int			$idprod          	Id of product or 0 if not a predefined product
  *  @param  Societe		$thirdparty_seller  Thirdparty with a ->country_code defined (FR, US, IT, ...)
- *	@param	int			$idprodfournprice	Id product_fournisseur_price (for supplier order/invoice)
+ *	@param	int			$idprodfournprice	Id product_fournisseur_price (for "supplier" order/invoice)
  *  @return int					         	<0 if KO, Vat rate if OK
  *  @see get_product_localtax_for_country
  */
 function get_product_vat_for_country($idprod, $thirdparty_seller, $idprodfournprice=0)
 {
-	global $db,$mysoc;
+	global $db,$conf,$mysoc;
 
-	if (! class_exists('Product')) {
-		require DOL_DOCUMENT_ROOT . '/product/class/product.class.php';
-	}
+	require_once DOL_DOCUMENT_ROOT . '/product/class/product.class.php';
 
 	$ret=0;
 	$found=0;
@@ -2931,7 +2929,7 @@ function get_product_vat_for_country($idprod, $thirdparty_seller, $idprodfournpr
 
 		if ($mysoc->country_code == $thirdparty_seller->country_code) // If selling country is ours
 		{
-			if ($idprodfournprice > 0)     // We want vat for product for a supplier order or invoice
+			if ($idprodfournprice > 0)     // We want vat for product for a "supplier" order or invoice
 			{
 				$product->get_buyprice($idprodfournprice,0,0,0);
 				$ret=$product->vatrate_supplier;
@@ -2952,23 +2950,28 @@ function get_product_vat_for_country($idprod, $thirdparty_seller, $idprodfournpr
 
 	if (! $found)
 	{
-		// If vat of product for the country not found or not defined, we return higher vat of country.
-		$sql = "SELECT taux as vat_rate";
-		$sql.= " FROM ".MAIN_DB_PREFIX."c_tva as t, ".MAIN_DB_PREFIX."c_pays as p";
-		$sql.= " WHERE t.active=1 AND t.fk_pays = p.rowid AND p.code='".$thirdparty_seller->country_code."'";
-		$sql.= " ORDER BY t.taux DESC, t.recuperableonly ASC";
-		$sql.= $db->plimit(1);
-
-		$resql=$db->query($sql);
-		if ($resql)
+		if (empty($conf->global->MAIN_VAT_DEFAULT_IF_AUTODETECT_FAILS))
 		{
-			$obj=$db->fetch_object($resql);
-			if ($obj)
+			// If vat of product for the country not found or not defined, we return higher vat of country.
+			$sql = "SELECT taux as vat_rate";
+			$sql.= " FROM ".MAIN_DB_PREFIX."c_tva as t, ".MAIN_DB_PREFIX."c_pays as p";
+			$sql.= " WHERE t.active=1 AND t.fk_pays = p.rowid AND p.code='".$thirdparty_seller->country_code."'";
+			$sql.= " ORDER BY t.taux DESC, t.recuperableonly ASC";
+			$sql.= $db->plimit(1);
+	
+			$resql=$db->query($sql);
+			if ($resql)
 			{
-				$ret=$obj->vat_rate;
+				$obj=$db->fetch_object($resql);
+				if ($obj)
+				{
+					$ret=$obj->vat_rate;
+				}
+				$db->free($sql);
 			}
+			else dol_print_error($db);
 		}
-		else dol_print_error($db);
+		else $ret=$conf->global->MAIN_VAT_DEFAULT_IF_AUTODETECT_FAILS;
 	}
 
 	dol_syslog("get_product_vat_for_country: ret=".$ret);
diff --git a/htdocs/product/class/product.class.php b/htdocs/product/class/product.class.php
index ffe63a62887..5690f2fbb8e 100644
--- a/htdocs/product/class/product.class.php
+++ b/htdocs/product/class/product.class.php
@@ -893,7 +893,7 @@ class Product extends CommonObject
 
 	/**
 	 *	Lit le prix pratique par un fournisseur
-	 *	On renseigne le couple prodfournprice/qty ou le triplet qty/product_id/fourn_ref)
+	 *	On renseigne le couple prodfournprice/qty ou le triplet qty/product_id/fourn_ref
 	 *
 	 *  @param     	int		$prodfournprice     Id du tarif = rowid table product_fournisseur_price
 	 *  @param     	double	$qty                Quantity asked
@@ -904,6 +904,8 @@ class Product extends CommonObject
 	function get_buyprice($prodfournprice,$qty,$product_id=0,$fourn_ref=0)
 	{
 		$result = 0;
+		
+		// We do select by searching with qty and prodfournprice
 		$sql = "SELECT pfp.rowid, pfp.price as price, pfp.quantity as quantity,";
 		$sql.= " pfp.fk_product, pfp.ref_fourn, pfp.fk_soc, pfp.tva_tx";
 		$sql.= " FROM ".MAIN_DB_PREFIX."product_fournisseur_price as pfp";
@@ -915,7 +917,7 @@ class Product extends CommonObject
 		if ($resql)
 		{
 			$obj = $this->db->fetch_object($resql);
-			if ($obj && $obj->quantity > 0)
+			if ($obj && $obj->quantity > 0)		// If found
 			{
 				$this->buyprice = $obj->price;                      // \deprecated
 				$this->fourn_pu = $obj->price / $obj->quantity;     // Prix unitaire du produit pour le fournisseur $fourn_id
@@ -926,7 +928,7 @@ class Product extends CommonObject
 			}
 			else
 			{
-				// On refait le meme select sur la ref et l'id du produit
+				// We do same select again but searching with qty, ref and id product
 				$sql = "SELECT pfp.rowid, pfp.price as price, pfp.quantity as quantity, pfp.fk_soc,";
 				$sql.= " pfp.fk_product, pfp.ref_fourn, pfp.tva_tx";
 				$sql.= " FROM ".MAIN_DB_PREFIX."product_fournisseur_price as pfp";
@@ -941,7 +943,7 @@ class Product extends CommonObject
 				if ($resql)
 				{
 					$obj = $this->db->fetch_object($resql);
-					if ($obj && $obj->quantity > 0)
+					if ($obj && $obj->quantity > 0)		// If found
 					{
 						$this->buyprice = $obj->price;                      // \deprecated
 						$this->fourn_pu = $obj->price / $obj->quantity;     // Prix unitaire du produit pour le fournisseur $fourn_id
@@ -952,7 +954,7 @@ class Product extends CommonObject
 					}
 					else
 					{
-						return -1;	// Ce produit existe chez ce fournisseur mais qte insuffisante
+						return -1;	// Ce produit n'existe pas avec cette ref fournisseur ou existe mais qte insuffisante
 					}
 				}
 				else