Windows authentication through VPN

Kind of an off-the-wall question. I am connected to my office from a remote locate using the VPN connection in 10.4.2. I am currently in a completely different domain using an internal IP on that network. I connect with the VPN and can access my Exchange email just fine. The probblem I am experiencing is when I try to get the network shares on our server. I punch in the proper authentication but it says the authentication has failed. The Exchange server is on the same server as these shares so I know my authentication is working along those lines. I can connect to the server just fine by Clicking Go-> Conenct to the Server, which lets me see the available shares, but I'm having difficulty authenticating.

Has anyone tried to authenticate to network shares across a VPN connection? This is my last hurdle before being able to competely switch over to my Mac.

Thanks!

Ariston