Index: pbx/pbx_realtime.c
===================================================================
--- pbx/pbx_realtime.c	(revision 334227)
+++ pbx/pbx_realtime.c	(working copy)
@@ -68,6 +68,8 @@
 	AST_APP_OPTION('p', OPTION_PATTERNS_DISABLED),
 });
 
+AST_THREADSTORAGE(appdata_buf);
+
 struct cache_entry {
 	struct timeval when;
 	struct ast_variable *var;
@@ -344,19 +346,23 @@
 		if (!ast_strlen_zero(app)) {
 			struct ast_app *a = pbx_findapp(app);
 			if (a) {
-				char appdata[512];
+				struct ast_str *appdata = ast_str_thread_get(&appdata_buf, 16);
 				char tmp1[80];
 				char tmp2[80];
 				char tmp3[EXT_DATA_SIZE];
 
-				appdata[0] = 0; /* just in case the substitute var func isn't called */
-				if(!ast_strlen_zero(tmp))
-					pbx_substitute_variables_helper(chan, tmp, appdata, sizeof(appdata) - 1);
+				if (!appdata) {
+					return -1;
+				}
+				ast_str_reset(appdata); /* just in case the substitute var func isn't called */
+				if (!ast_strlen_zero(tmp)) {
+					ast_str_substitute_variables(&appdata, 0, chan, tmp);
+				}
 				ast_verb(3, "Executing [%s@%s:%d] %s(\"%s\", \"%s\")\n",
 						chan->exten, chan->context, chan->priority,
 						 term_color(tmp1, app, COLOR_BRCYAN, 0, sizeof(tmp1)),
 						 term_color(tmp2, chan->name, COLOR_BRMAGENTA, 0, sizeof(tmp2)),
-						 term_color(tmp3, S_OR(appdata, ""), COLOR_BRMAGENTA, 0, sizeof(tmp3)));
+						 term_color(tmp3, ast_str_buffer(appdata), COLOR_BRMAGENTA, 0, sizeof(tmp3)));
 				manager_event(EVENT_FLAG_DIALPLAN, "Newexten",
 							  "Channel: %s\r\n"
 							  "Context: %s\r\n"
@@ -365,9 +371,9 @@
 							  "Application: %s\r\n"
 							  "AppData: %s\r\n"
 							  "Uniqueid: %s\r\n",
-							  chan->name, chan->context, chan->exten, chan->priority, app, !ast_strlen_zero(appdata) ? appdata : "(NULL)", chan->uniqueid);
-				
-				res = pbx_exec(chan, a, appdata);
+							  chan->name, chan->context, chan->exten, chan->priority, app, ast_str_buffer(appdata), chan->uniqueid);
+
+				res = pbx_exec(chan, a, ast_str_buffer(appdata));
 			} else
 				ast_log(LOG_NOTICE, "No such application '%s' for extension '%s' in context '%s'\n", app, exten, context);
 		} else {