Pokerstars in particular are clamping down on VPN users whilst abroad. I read a whole load about it in on 2p2 in the autumn while in a similar situation.
Lots of players where banned (I don't know how long for) when their VPN dropped and their real IP was momentarily exposed. I decided not to risk it with stars.
However, there may be a small hope for you;
How to make a program use only a vpn tunnel
I happen to use SwissVPN anyway to guard my computers security (
just one cool website about security) and at least for me, if the VPN drops (but not my internet connection) so does my connection to the poker client.
Hope that made sense and although I won't recommend playing Stars while you are in the US I wish you luck if you do.
- DaPhunk