diff --git a/library/M3UA_Templates.ttcn b/library/M3UA_Templates.ttcn
index 02b493c..1063b50 100644
--- a/library/M3UA_Templates.ttcn
+++ b/library/M3UA_Templates.ttcn
@@ -81,7 +81,7 @@
 		version := c_M3UA_VERSION,
 		reserved := '00'O,
 		messageClassAndType := '0301'O,
-		messageLength := 0, // overwritten
+		messageLength := ?, // overwritten
 		messageParameters := {
 			aSP_Identifier := tr_M3UA_asp_id(aspid),
 			info_String := *