m0n0wall Forum - Cannot initiate IPSEC tunnel because of NAT

My problem has to do with both NAT and IPSEC VPN, so it does not fit into any one category. Hence being in the general questions.

The jist of it:
I am tying to terminate a VPN to one internet IP address, through my LAN, and then NAT it out to various port forwards.

I have searched the the internet and various forums far and wide and have not found a solution. I have to assume that what I am trying to do is possible and that someone has done it before.

More detailed background:
I have a connection to a remote network set up using an IPSEC VPN. The remote gateway is xxx.xxx.xxx.15, and the remote network is xxx.xxx.xxx.23. My local VPN gateway is the WAN interface with an IP address of yyy.yyy.yyy.72, and my local network that I am making available via IPSEC is a CARP address of yyy.yyy.yyy.77 on the WAN interface. NAT redirection is turned on so that yyy.yyy.yyy.77 is accessible from within the firewall. yyy.yyy.yyy.77 uses PAT/NAT to redirect VPN clients to their true destination inside my network.

Almost all of the above is working as it should. The problem that I am running into is that I can only bring the tunnel up from the remote side. Can anyone help me solve this? It would be greatly appreciated.