library/IPA: use tr_ASP_IPA_EV instead of inline templates

This way we can easily add new parameters to ASP_IPA_Event.

Change-Id: Icc37286fcb4d43836d56a26424ecb9dcba58d1f1
diff --git a/bsc-nat/BSC_MS_Simulation.ttcn b/bsc-nat/BSC_MS_Simulation.ttcn
index 0582576..0a057a3 100644
--- a/bsc-nat/BSC_MS_Simulation.ttcn
+++ b/bsc-nat/BSC_MS_Simulation.ttcn
@@ -131,7 +131,7 @@
 	/* Initial delay to wait for IPA connection establishment */
 	T.start;
 	alt {
-	[] SCCPLITE_IPA_CTRL.receive(ASP_IPA_Event:{up_down := ASP_IPA_EVENT_UP}) { }
+	[] SCCPLITE_IPA_CTRL.receive(tr_ASP_IPA_EV(ASP_IPA_EVENT_UP)) { }
 	[] T.timeout {
 		setverdict(fail, "Timeout CTRL waiting for ASP_IPA_EVENT_UP");
 		mtc.stop;