diff --git a/htdocs/core/class/html.formmail.class.php b/htdocs/core/class/html.formmail.class.php
index d7ab17e60c4..6c411b60e66 100644
--- a/htdocs/core/class/html.formmail.class.php
+++ b/htdocs/core/class/html.formmail.class.php
@@ -1133,6 +1133,9 @@ class FormMail extends Form
 				$vars['__SECUREKEYPAYPAL_MEMBER__']='';
 			}
 		}
+		
+		$vars=complete_substitutions_array($vars, $langs, null, null);
+		
 		return $vars;
 	}
 
diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index 857ddc6eec2..b6cf92aa81d 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -4953,7 +4953,8 @@ function make_substitutions($text, $substitutionarray, $outputlangs=null)
 }
 
 /**
- *  Complete the $substitutionarray with more entries
+ *  Complete the $substitutionarray with more entries.
+ *  Can also add substitution keys coming from external module that had set the "substitutions=1" into module_part array. In this case, method completesubstitutionarray provided by module is called. 
  *
  *  @param  array		$substitutionarray		Array substitution old value => new value value
  *  @param  Translate	$outputlangs            Output language