Vista VPN Default gateway problem

Hello everyone
in windows XP i was UNcheck the default gateway for the vpn connection i
create , so i can access the remote network without to have the destination
gateway as my internet gateway

when i do uncheck the same box in windows vista vpn connection, it come back
to checked by default when connected??
i installed SP1 for vista,

is there any solution may help ??

thank you.

Ahmad Sabry