diff --git a/bsc/MSC_ConnectionHandler.ttcn b/bsc/MSC_ConnectionHandler.ttcn
index 3cc8f8a..c7f6495 100644
--- a/bsc/MSC_ConnectionHandler.ttcn
+++ b/bsc/MSC_ConnectionHandler.ttcn
@@ -379,10 +379,12 @@
 private function UnitdataCallback(PDU_BSSAP bssap)
 runs on RAN_Emulation_CT return template PDU_BSSAP {
 	var template PDU_BSSAP resp := omit;
+	var boolean append_osmux_support := g_ran_ops.use_osmux and
+					    (g_ran_ops.transport == BSSAP_TRANSPORT_AoIP);
 
 	/* answer all RESET with a RESET ACK */
-	if (match(bssap, tr_BSSMAP_Reset(g_ran_ops.use_osmux))) {
-		resp := ts_BSSMAP_ResetAck(g_ran_ops.use_osmux);
+	if (match(bssap, tr_BSSMAP_Reset(append_osmux_support))) {
+		resp := ts_BSSMAP_ResetAck(append_osmux_support);
 	}
 
 	return resp;