SRX VPN and NAT

We are starting to provide preconfigured SRX100s to our clients to securely connect to our hosted datacenter over IPSEC.

We would like to isolate the networks on both sides from IP conflicts. We would also like to make all the configuration changes on the SRX100s if at all possible.

We have tried static NAT with limited success, possibly because attempts at working with a zone where the VPN terminates doesn't seem to work.

Does anyone have any suggestions for a configuration example? Does static NAT make sense, or should we try source and destination NAT?

Thanks!

...Ralph Johnston