diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 5741458..8300f8e 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -1914,7 +1914,8 @@
 	len := 0, /* overwritten */
 	m := false,
 	el := 1,
-	payload := enc_GsmRrL3Message(valueof(l3))
+	payload := enc_GsmRrL3Message(valueof(l3)),
+	padding := ''O
 }
 
 /* handle incoming downlink SACCH and respond with uplink SACCH (meas res) */