Loopback changing port (RDP) in V18

Hi,

i have an RDP server exposed on a non standard port, say 5000

from outside i connect to my.site.com:5000 and the Sophos connects me to the internal RDP server, no problem

when i am inside my network i can't use the same RDP preset and i must use the internal 192.168.10.10 (on default 3389 port)

I tried to setup a Loopback like the one Sophos automatically created for my webserver that works, the only difference i can see is that the RDP has a port translation and doesn't work

i can successfully ping my.site.com from inside and it gives me the external IP

Thanks