IPSec and overlapping subnets

We have a situation that we have always worked to avoid in the past by renumbering networks, but it's not an option this time. Namely, We need to connect our subnet 10.100.0.0/23 over an IPSec tunnel to a location that has an overlapping subnet.

So, we need to NAT traffic back and forth, and I'm frankly not certain how to achieve it. Basically, the remote side wants to pretend that we are 10.100.252.0/23, so we need to do some magic to translate the source and destnation subnets.

Can anyone point out a good method to achieve this?

Tom