Well, I am not sure why do you want to extend your Vlans over the WAN. Is there any special requirement to do the same. If your over all WAN connectivity would have been on ethernet, then it would have been fairly simple to extend the Vlans over the WAN. You could have configured all the remote locations to be the same VTP domain.
The connectivity here is a little different I guess, the only way we can achieve it by using IRB (Integrated routing and bridging) on the router. This is useful in the scenario where you want to have a single common LAN across the WAN. I am not sure if you can use it for multiple vlans acorss the WAN as you need a lots of FE ports on the routers to do it.
http://cio.cisco.com/univercd/cc/td/doc/product/l3sw/4840g/ios_12/1_5/config/4840br.htm
HTH,Please rate if it does.
-amit singh