SIP_Templates: Allow passing WwwAuthenticate to ts_SIP_msgh_std

The field could already be passed to its tr_* counterpart, but not the
the ts_* one.

Change-Id: Ibc6cc5320f24ce82165c1b2140bad30cb356f8ae
diff --git a/library/SIP_Templates.ttcn b/library/SIP_Templates.ttcn
index e22646c..2498f49 100644
--- a/library/SIP_Templates.ttcn
+++ b/library/SIP_Templates.ttcn
@@ -454,7 +454,8 @@
 		template (omit) ContentType content_type := omit,
 		template (omit)Authorization authorization := omit,
 		template (value) Method_List allow_methods := c_SIP_defaultMethods,
-		template (omit) Expires expires := omit
+		template (omit) Expires expires := omit,
+		template (omit) WwwAuthenticate wwwAuthenticate := omit
 	) modifies ts_SIP_msgHeader_empty := {
 	allow := {
 		fieldName := ALLOW_E,
@@ -489,7 +490,8 @@
 			"osmo-ttcn3-hacks/0.23"
 		}
 	},
-	via := via
+	via := via,
+	wwwAuthenticate := wwwAuthenticate
 }
 
 function tr_AllowMethods(template Method_List allow_methods) return template Allow {