diff --git a/htdocs/cashdesk/validation_verif.php b/htdocs/cashdesk/validation_verif.php
index 5775a3c9388..3328fa52886 100644
--- a/htdocs/cashdesk/validation_verif.php
+++ b/htdocs/cashdesk/validation_verif.php
@@ -57,14 +57,29 @@ switch ($action)
 		$invoice->date=dol_now();
 		$invoice->type= Facture::TYPE_STANDARD;
 		
-		// TODO
 		// To use a specific numbering module for POS, reset $conf->global->FACTURE_ADDON and other vars here
-		// and restore after values just after
+		// and restore values just after
+		$sav_FACTURE_ADDON='';
+		if (! empty($conf->global->POS_ADDON))
+		{
+			$sav_FACTURE_ADDON = $conf->global->FACTURE_ADDON;
+			$conf->global->FACTURE_ADDON = $conf->global->POS_ADDON;
+
+			// To force prefix only for POS with terre module
+			if (! empty($conf->global->POS_NUMBERING_TERRE_FORCE_PREFIX)) $conf->global->INVOICE_NUMBERING_TERRE_FORCE_PREFIX = $conf->global->POS_NUMBERING_TERRE_FORCE_PREFIX;
+			// To force prefix only for POS with mars module
+			if (! empty($conf->global->POS_NUMBERING_MARS_FORCE_PREFIX)) $conf->global->INVOICE_NUMBERING_MARS_FORCE_PREFIX = $conf->global->POS_NUMBERING_MARS_FORCE_PREFIX;
+			// To force rule only for POS with mercure
+			//...
+		}
 		
 		$num=$invoice->getNextNumRef($company);
 
-		// TODO Restore save values
-		
+		// Restore save values
+		if (! empty($sav_FACTURE_ADDON))
+		{
+			$conf->global->FACTURE_ADDON = $sav_FACTURE_ADDON;
+		}
 		
 		$obj_facturation->numInvoice($num);
 
diff --git a/htdocs/core/modules/facture/mod_facture_mars.php b/htdocs/core/modules/facture/mod_facture_mars.php
index e477e086fe0..578ed1a16ff 100644
--- a/htdocs/core/modules/facture/mod_facture_mars.php
+++ b/htdocs/core/modules/facture/mod_facture_mars.php
@@ -37,6 +37,18 @@ class mod_facture_mars extends ModeleNumRefFactures
 	var $prefixcreditnote='AV';
 	var $error='';
 
+	
+	/**
+	 * Constructor
+	 */
+	function __construct()
+	{
+		if (! empty($conf->global->INVOICE_NUMBERING_MARS_FORCE_PREFIX))
+		{
+			$this->prefixinvoice = $conf->global->INVOICE_NUMBERING_MARS_FORCE_PREFIX;
+		}
+	}
+	
 	/**
 	 *  Renvoi la description du modele de numerotation
 	 *
diff --git a/htdocs/core/modules/facture/mod_facture_terre.php b/htdocs/core/modules/facture/mod_facture_terre.php
index 31d8eac736b..c0497f5fb5c 100644
--- a/htdocs/core/modules/facture/mod_facture_terre.php
+++ b/htdocs/core/modules/facture/mod_facture_terre.php
@@ -35,6 +35,18 @@ class mod_facture_terre extends ModeleNumRefFactures
 	var $prefixdeposit='AC';
 	var $error='';
 
+	
+	/**
+	 * Constructor
+	 */
+	function __construct()
+	{
+		if (! empty($conf->global->INVOICE_NUMBERING_TERRE_FORCE_PREFIX))
+		{
+			$this->prefixinvoice = $conf->global->INVOICE_NUMBERING_TERRE_FORCE_PREFIX;
+		}
+	}
+	
 	/**
 	 *  Renvoi la description du modele de numerotation
 	 *