The Bat! times out when virus-scanning large mails

Dad has been having some problems with The Bat! timing out when sending or receiving large mails (attached pictures) because Comodo Antivirus is scanning them before passing them on.
Is this an issue that needs to be fixed in The Bat! or in the antivirus? Is there some way for Comodo to update The Bat! on its progress (it sits too long with no progress shown in the connection window)?
For now we have disabled outgoing scans but don’t really want to disable incoming scans (though we did for one to prove the source of the timeout and to get that mail).

In The Bat! Right click on the account name → properties → in the property window click on transport, on the right hand side you’ll see ‘Server Timeout’, set it to something higher, goes up to 999999 sec. I’m talking about The Bat! Pro and have no idea if this works in the free version.