SIP_Templates: Allow setting transport in Via templates

This is needed when using IMS, since TCP is used.

Change-Id: Id45491615bcb5c074ef4fc298cbb24b2e034972d
diff --git a/library/SIP_Templates.ttcn b/library/SIP_Templates.ttcn
index 3492dc4..e22646c 100644
--- a/library/SIP_Templates.ttcn
+++ b/library/SIP_Templates.ttcn
@@ -372,22 +372,24 @@
 	mediaType := "application/sdp"
 };
 
-template (value) Via ts_Via_from(template (value) HostPort addr) := {
+template (value) Via ts_Via_from(template (value) HostPort addr,
+				 template (value) charstring transport := "UDP") := {
 	fieldName := VIA_E,
 	viaBody := {
 		{
-			sentProtocol := { "SIP", "2.0", "UDP" },
+			sentProtocol := { "SIP", "2.0", transport },
 			sentBy := addr,
 			viaParams := omit
 		}
 	}
 }
 template (present) Via tr_Via_from(template (present) HostPort host_port := ?,
+				   template (present) charstring transport := ?,
 				   template SemicolonParam_List viaParams := *) := {
 	fieldName := VIA_E,
 	viaBody := {
 		{
-			sentProtocol := { "SIP", "2.0", "UDP" },
+			sentProtocol := { "SIP", "2.0", ? },
 			sentBy := host_port,
 			viaParams := viaParams
 		}