NAT VPN Traffic

So here is the scenario that I have. We use our Vyatta to establish IPSec VPNs with our customer’s network. It seems that most everybody when they set up a router let’s it default to for their local subnet. This poses a problem since the subnets have to be unique. A lot of the time our customers have a sonicwall or similar device that will handle NATing VPN traffic on their side. Quite frequently the customer has a lower end router that will not do this.

Is there a way on the Vyatta to NAT traffic for a specific VPN. Let’s say I have VPN A with remote subnet of and I want to set up VPN B, VPN B has a remote subnet of so that won’t work, is there a way to set that VPN up with a different subnet and have it NAT the traffic or can this only be done on the source side?