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;
diff --git a/library/RAN_Emulation.ttcnpp b/library/RAN_Emulation.ttcnpp
index 85ae084..ba018b4 100644
--- a/library/RAN_Emulation.ttcnpp
+++ b/library/RAN_Emulation.ttcnpp
@@ -445,6 +445,11 @@
 type function BssmapUnitdataCallback(PDU_BSSAP bssap)
 runs on RAN_Emulation_CT return template PDU_BSSAP;
 
+private function append_osmux_ie()
+runs on RAN_Emulation_CT return boolean {
+	return g_ran_ops.use_osmux and (g_ran_ops.transport == BSSAP_TRANSPORT_AoIP);
+}
+
 /* handle common Unitdata such as Paging */
 private function CommonBssmapUnitdataCallback(PDU_BSSAP bssap)
 runs on RAN_Emulation_CT return template PDU_BSSAP {
@@ -469,14 +474,15 @@
 private function f_bssap_wait_for_reset() runs on RAN_Emulation_CT {
 	var BSSAP_N_UNITDATA_ind ud_ind;
 	timer T := 20.0;
+	var boolean append_osmux_support := append_osmux_ie();
 
 	T.start;
 	alt {
-	[] BSSAP.receive(tr_BSSAP_UNITDATA_ind(?, ?, tr_BSSMAP_Reset(g_ran_ops.use_osmux))) -> value ud_ind {
+	[] BSSAP.receive(tr_BSSAP_UNITDATA_ind(?, ?, tr_BSSMAP_Reset(append_osmux_support))) -> value ud_ind {
 		BSSAP.send(ts_BSSAP_UNITDATA_req(ud_ind.callingAddress, ud_ind.calledAddress,
-			   ts_BSSMAP_ResetAck(g_ran_ops.use_osmux)));
+			   ts_BSSMAP_ResetAck(append_osmux_support)));
 		}
-	[] as_reset_ack();
+	[] as_reset_ack(append_osmux_support);
 	[] BSSAP.receive {
 		repeat;
 		}
@@ -489,14 +495,15 @@
 
 function f_bssap_reset(SCCP_PAR_Address peer, SCCP_PAR_Address own) runs on RAN_Emulation_CT {
 	timer T := 5.0;
+	var boolean append_osmux_support := append_osmux_ie();
 
-	BSSAP.send(ts_BSSAP_UNITDATA_req(peer, own, ts_BSSMAP_Reset(0, g_ran_ops.use_osmux)));
+	BSSAP.send(ts_BSSAP_UNITDATA_req(peer, own, ts_BSSMAP_Reset(0, append_osmux_support)));
 	T.start;
 	alt {
-	[] BSSAP.receive(tr_BSSAP_UNITDATA_ind(own, peer, tr_BSSMAP_ResetAck(g_ran_ops.use_osmux))) {
+	[] BSSAP.receive(tr_BSSAP_UNITDATA_ind(own, peer, tr_BSSMAP_ResetAck(append_osmux_support))) {
 		log("Received RESET-ACK in response to RESET, we're ready to go!");
 		}
-	[] as_reset_ack();
+	[] as_reset_ack(append_osmux_support);
 	[] BSSAP.receive { repeat };
 	[] T.timeout {
 		setverdict(fail, "Timeout waiting for RESET-ACK after sending RESET");
@@ -728,7 +735,7 @@
 	f_ML3_patch_seq_nr(seq_nr, enc_l3);
 }
 
-private altstep as_reset_ack() runs on RAN_Emulation_CT {
+private altstep as_reset_ack(boolean append_osmux_support := false) runs on RAN_Emulation_CT {
 #ifdef RAN_EMULATION_BSSAP
 	var BSSAP_N_UNITDATA_ind ud_ind;
 #endif
@@ -736,10 +743,10 @@
 	var RANAP_N_UNITDATA_ind rud_ind;
 #endif
 #ifdef RAN_EMULATION_BSSAP
-	[] BSSAP.receive(tr_BSSAP_UNITDATA_ind(?, ?, tr_BSSMAP_Reset(g_ran_ops.use_osmux))) -> value ud_ind {
+	[] BSSAP.receive(tr_BSSAP_UNITDATA_ind(?, ?, tr_BSSMAP_Reset(append_osmux_support))) -> value ud_ind {
 		log("Respoding to inbound RESET with RESET-ACK");
 		BSSAP.send(ts_BSSAP_UNITDATA_req(ud_ind.callingAddress, ud_ind.calledAddress,
-			   ts_BSSMAP_ResetAck(g_ran_ops.use_osmux)));
+			   ts_BSSMAP_ResetAck(append_osmux_support)));
 		repeat;
 	}
 #endif