If the PC connecting is a sever OS you could just enable plane jayne routing to it, failing that ICS should be able to perform as needed if a virtual interface is created for the VPN network (one almost always is). You will need to add some static routes and most likely other changes reguardless of these methods, this is a fairly complicated setup.
That said if I was running the corporate IT infrastructure I would not take kindly to this. I am not telling you what to do, I was just compelled to add that.