How do i link a NAT rule to a firewall rule?

I created a new rule which allows traffic originating from VPN subnet to the external IP address.

I verified in the logs that the traffic passes by unobstructed. Also verified in SSL VPN settings that the particular VPN profile contains that IP address that is allowed to be reached (in other words - when i connect to Sophos Connect client, i see that remote IP addr under "Networks" tab", and also this IP address is present in local machines route table with the next hop being VPN subnet's gateway)

However, i still cannot reach the remote IP address and the only possible problem that i may think of is that the local IP of the VPN subnet is not being translated into a public IP.

And as far as i checked, there is no intuitive way how to verify if thats the case or how to fix it. Any advice?