How to keep VPN running to switch user

Hey all - just upgraded to Windows Vista on my work laptop. Normally if I was
in the office I would join my domain, then create my standard "mike" user but
logging off administrator and logging in as "mike" under the new domain.

But because I am not near an office, what I have done in the past (WinXP)
was start up my Nortel VPN client as Administrator do a Fast User Switch and
log in as "mike" - the VPN connection would stay up and I would create my new
"mike" account on my PC - without this connection it fails to validate of
course.

Therefore my question is how to I get around Vista killing off my VPN
connection - I have tried creating a Microsoft VPN connection, but
unfortunately it does not support all the security userid/passwords as
Nortel's VPN therefore It fails to login into my office - therefore I can not
setup this VPN functionality on the login screen.

Any suggestion on how to switch users with out losing my VPN connection
and/or able to use Nortel (Custom) VPN at the login prompt.

Thanks...
....Mike