Ok, then I think we can make this work. You obviously seem familiar enough with Linux, so here's the basic commands that should make this work (you will probably need to tweak it):
# The following lines will route your office traffic through the VPN tunnel whilst all other traffic goes out through the BlackBerry directly to the Internet
# In each line, after "dev", enter the VPN interface number
route add -net 10.10.0.0 netmask 255.255.0.0 dev vpn0
route add -net 10.20.0.0 netmask 255.255.0.0 dev vpn0
route add -net 10.30.0.0 netmask 255.255.0.0 dev vpn0
I'm not guaranteeing this will work, but it's the best I've got.