Simple DNAT rule created with Server Access Assistant does not work

Hi all,

I created a DNAT rule with Server Access Assistant under SFOS 18.0.5 but it does not work at all. Here are the screenshots of the rules:

NAT rule:

Firewall rule:

Service definition:

Here is the TCPDUMP. Out interface Port2_ppp for an internal destination IP looks surprising to me...  

Any help would be very appreciated as I am out of ideas.

Best regards

Carsten