SMB file transfer Lion

I am have a few issues with file sharing between my mac mini server and windows Pcs since i upgraded to Lion server. I have it working when I am on the network but when I am outside the network is when the problems start. First I have yet to be able to VPN to the network (which i use to be able to do with snow leopard) with windows and after a very lengthy conversation with apple last night they say its a windows issue even though the pc is the same and the only thing that has changed is the os on the mac server. So i decided to try to just set up a SMB file share instead of using a VPN so remote users with windows could still access files. After another lengthy conversation with apple and opening ports, dropping firewalls and putting the server in the DMZ they again said it is a windows issue. Has anyone been able to copy and send files to/ from a mac mini lion server and a windows pc? Thanks in advance for any help.