Setting up a VPN - Routing issues?

[mistercrabb]

Hi all, I'm a bit stumped at the moment. This is a little personal project I'm trying to do.

Basically, I have 2 sites, Site A and Site B.
Site A has a Windows Home Server, and I have enabled VPN by following this guide.

I want to connect to that server via VPN from a single client machine at Site B. I can connect to it fine using the Windows 7 VPN software over PPTP, and I've enabled split tunneling.

Problems:

• Client machine at Site B cannot resolve UNC names at Site A (think NetBIOS is blocked somewhere?)
• Client at Site B can connect to Site A through Windows Explorer by IP address (192.168.27.100), and can see the shared folders but gets denied access when trying to open them, despite being logged in on an account with share access.
• Client PC loses access to LAN at Site B - Outlook starts shouting for passwords, printers fail and network drives appear offline. This doesn't happen immediately.

I'm guessing it's something to do with routing because the PC at Site B loses it's own LAN after a while ("use default gateway on remote network" is disabled which is supposed to allow split tunnelling).

Both sites use different subnets.
I just want the Client PC to VPN into the server at Site A while maintaining access to it's own network.

Any ideas?
I know split tunnelling is normally best avoided by the way!