As I have explained, it is not possible to use SNC between SAP GUI and SAP Router. if it was possible then i am sure a third party or SAP themselves would have provided something for this. The SAP Router is using SNC at lower level in protocol stack and SAP GUI is using SNC at high level in protocol stack (application level).
In summary, the options are:
1. Open hole in firewall so that SAP GUI (authenticated using SNC) can connect to ECC through the hole (no SAP Router involved)
2. Put SAP Router on users workstation so that SAP Router can talk to SAP Router and SAP GUI (with SNC) can be used over the SAP Router <--> SAP Router connection.
3. Use a VPN
Thanks
Tim