ENDIAN Firewall - SMTP proxy, relay to a non-default port problem

Hello,
I've just freshly installed a new EFW server in virtual environment, connected to a LAN. I'd like to use EFW as a spam-filter mail-relay solution.
So it accepts e-mails from the world, spam-filter them, and then relays them to a final mailbox server.
My problem is, the final mailbox server listens SMTP connections on port TCP 2525, and it seems EFW can not be configured to relay e-mails to a non-standard SMTP port.

On the web admin interface, I tried to go to "Proxy > SMTP > Incoming domains" configuration page and I tried to set Mailserver value of my domain to [10.0.0.3]:2525 as this should be the format for relaying e-mails to an IP-address and a non-standard SMTP port.
Unfortunately after I apply the changes, incorrect values are written in /etc/postfix/transport and /etc/postfix/relay_domains files. In these files I can see values like this: smtp:[[10.0.0.3]:2525]
This format is incorrect, so the mail-relay doesn't work. If I edit these files and postmap them, then mail-relay works fine, until the next settings apply.
I think this is some kind of bug of the web admin pages.

Any idea how to workaround or fix this problem?