Remote accessing file shares problem

NRC,
I'm sure this is too late for you, but perhaps it will help someone else (as it would've helped me two weeks ago). I had a similar problem- an externally controlled VPN concentrator, outside my control, bringing VPN users into my network. In my case it was a Nortel concentrator. My vendor could not provide name resolution, and as not to conflict with my corporate internal name resolution I chose a seperate DNS server using third party software (Simple DNS Plus) running on one computer that my VPN clients would point to. I battled this issue for two weeks- I could ping all DC's from externally, connected VPN, but would always be prompted for login credentials when connecting to network shares not on the same subnet the VPN entry point resided on. The end resolution- I needed a PTR record in my DNS. I found the fix roundabout, before I knew the actual fix. I created the PTR record to my PDC emulator DC and that was it- problem solved.

Good luck.