diff --git a/library/IPA_Emulation.ttcnpp b/library/IPA_Emulation.ttcnpp
index 1bfc8dc..0125c3a 100644
--- a/library/IPA_Emulation.ttcnpp
+++ b/library/IPA_Emulation.ttcnpp
@@ -110,12 +110,14 @@
 	RSL_Message	rsl
 };
 
-template (value) ASP_RSL_Unitdata ts_ASP_RSL_UD(IpaStreamId sid, template (value) RSL_Message rsl) := {
+template (value) ASP_RSL_Unitdata ts_ASP_RSL_UD(template (value) RSL_Message rsl,
+						IpaStreamId sid := IPAC_PROTO_RSL_TRX0) := {
 	streamId := sid,
 	rsl := rsl
 }
 
-template ASP_RSL_Unitdata tr_ASP_RSL_UD(template IpaStreamId sid, template RSL_Message rsl) := {
+template ASP_RSL_Unitdata tr_ASP_RSL_UD(template (present) RSL_Message rsl,
+					template IpaStreamId sid := IPAC_PROTO_RSL_TRX0) := {
 	streamId := sid,
 	rsl := rsl
 }