Ok, I finally have this working and just in time to receive my N800 tomorrow (couldn't resist). So my 770 is now talking to my HTC TyTN just fine. I changed the ROM build from Black Dymond to the AT&T release build. I then installed the DUN cab and the modemlink cab and imported the registry file (missed this step the first time as I didn't have a reg program at the time that did import). I followed the rest of the steps and now have the two connected.

I hope its just as 'easy' when I get the N800 tomorrow!

Thanks to all for the assistance on this ..

Regards,
David