Index: res/ael/pval.c
===================================================================
--- res/ael/pval.c	(revision 233874)
+++ res/ael/pval.c	(working copy)
@@ -4430,13 +4430,15 @@
 			for (lp=p->u2.arglist; lp; lp=lp->next) {
 				/* for each arg, set up a "Set" command */
 				struct ael_priority *np2 = new_prio();
+				int arg_prev=argc++;
 				np2->type = AEL_APPCALL;
 				if (!ast_compat_app_set) {
 					np2->app = strdup("MSet");
+					snprintf(buf,sizeof(buf),"LOCAL(%s)=${ARG%d},ARG%d=\"\"", lp->u1.str, arg_prev, arg_prev);
 				} else {
 					np2->app = strdup("Set");
+					snprintf(buf,sizeof(buf),"LOCAL(%s)=${ARG%d}|ARG%d=\"\"", lp->u1.str, arg_prev, arg_prev);
 				}
-				snprintf(buf,sizeof(buf),"LOCAL(%s)=${ARG%d}", lp->u1.str, argc++);
 				remove_spaces_before_equals(buf);
 				np2->appargs = strdup(buf);
 				linkprio(exten, np2, NULL);