I have a subnet 192.168.10.0/24 after my monowall firewall with a static
internet ip.

Now I've made a vpn connection to a other astaro firewall with subnet
192.168.0.0/24

In that subnet there is a exchange server with webmail with ip
192.168.0.2

But the internet provider is blocking all incoming ports under 1024 and
I don't want to change the port the webserverruns on.

So I made the vpn tunnel and it works super.. most say between the
astaro box and the monowall the vpn tunnel is more stable than between 2
astaro boxes.. I did a incoming nat translation to 192.168.0.2 port 80.
But it doest work

To a real local server 192.168.10.10 it does but to the ip in the vpn
tunnel it doesn't... 

Now I know on a cisco we had the same problem and solved it by natting
it to the loopback interface and then nat the loopback to the ip.

But don't know if this is possible on a monowall.

I know advaced setup but would like to know if possible.