epdg: Introduce test TC_s2b_CreateSession_rejected

Related: OS#6371
Change-Id: Ide1df9e359b12094f82e54a7824c83f515aedcc3
diff --git a/library/GTPv2_Templates.ttcn b/library/GTPv2_Templates.ttcn
index a86145d..752e85c 100644
--- a/library/GTPv2_Templates.ttcn
+++ b/library/GTPv2_Templates.ttcn
@@ -145,7 +145,6 @@
 	}
 }
 
-
 /* 8.4-1 */
 type enumerated GTP2C_Cause {
 	Local_Detach 				(2),
@@ -167,7 +166,8 @@
 	New_PDN_type_due_to_network_preference	(18),
 	New_PDN_type_due_to_single_address_bearer_only (19),
 	/* ... */
-	Context_Not_Found			(64)
+	Context_Not_Found			(64),
+	APN_access_denied__no_subscription	(93)
 } with { variant "FIELDLENGTH(8)" encode "RAW" };
 
 /* 8.4 */
@@ -1021,13 +1021,14 @@
 template (value) PDU_GTPCv2
 ts_GTP2C_CreateSessionResp(template (value) OCT4 d_teid,
 			   template (value) OCT3 seq,
-			   template (value) FullyQualifiedTEID_List fteids,
-			   template (value) PDN_AddressAllocation addr,
+			   template (value) GTP2C_Cause cause := Request_accepted,
+			   template (omit) FullyQualifiedTEID_List fteids := omit,
+			   template (omit) PDN_AddressAllocation addr := omit,
 			   template (omit) BearerContextGrouped_List bearerContextGrouped := omit,
 			   template (omit) APCO apco := omit) :=
 ts_PDU_GTP2C(d_teid, seq, '21'O, {
 	createSessionResponse := {
-		cause := ts_GTP2C_Cause(Request_accepted, '0'B),
+		cause := ts_GTP2C_Cause(cause, '0'B),
 		changeReportingAction := omit,
 		cSG_InformationReportingAction := omit,
 		heNBInformationReporting := omit,