Hi
yes this should be no problem - you can use policy NAT for that, e.g.
access-list polnat permit ip 10.10.10.0 255.255.255.0 172.16.0.0 255.255.0.0
nat (outside) 1 access-list polnat outside
global (inside) 1 192.168.1.1
where 10.10.10.x is the vpn pool, 172.16.x.x is the partner network, and 192.168.1.1. is the address you want to NAT the clients to (this can also be "interface" if you want to use the Pix's address, or it can be a range of addresses if you want to do NAT instead of PAT).
Note that if you have nat exemption configured (aka "nat 0"), then you have to make sure the traffic to be natted does not match the nat exemption (otherwise the nat exemption takes precedence over the policy nat).
hth
Herbert