PAT or NAT through IPSEC Tunnel

[w.hackl]

Hi there ,
I've got a problem with NAT Through a connected IPSEC VPN.
Following network diagram :

The client can access the ports on the Host 10.10.1.1 through the tunnel.
But I want to define a Port forward on the WAN side to access a port on the 10.10.1.1

Perhaps I'm not to see the forest for the trees but I can't establish a connection .

Any suggestions ?
Regards
w.