diff --git a/modules/voipcall/voipscript.inc b/modules/voipcall/voipscript.inc
index e779cc3..25b39bc 100644
--- a/modules/voipcall/voipscript.inc
+++ b/modules/voipcall/voipscript.inc
@@ -1245,10 +1245,13 @@ function _voipscript_expand_variables($str, $vars) {
 
   $eval = substr($str, 0, 1) == '^';
   $regex = '/\%([a-z_]\w+)/';
-  //$regex = '/\%(\w+)/e';
-  $replacement = "_voipscript_replace_variable('\$1', \$vars, \$eval);" ;
-  //$replacement = "_voipscript_replace_variable(\$1, \$vars, \$eval);" ;
-  $res = preg_replace($regex, $replacement ,$str);
+
+  $res = preg_replace_callback(
+    $regex,
+    function($matches) use ($vars, $eval) { return _voipscript_replace_variable($matches, $vars, $eval); },
+    $str
+  );
+
   if($eval) {
     ob_start();
     $expr = substr($res, 1);
@@ -1262,7 +1265,8 @@ function _voipscript_expand_variables($str, $vars) {
   return $res;
 }
 
-function _voipscript_replace_variable($var_name, $vars, $eval) {
+function _voipscript_replace_variable($matches, $vars, $eval) {
+  $var_name = $matches[1];
   if(isset($vars[$var_name])) {
     $expanded = _voipscript_expand_variables($vars[$var_name], $vars);
     if($eval) {