well i tried so many times to make Pop3 accounts work over a proxy, but couldn't work it out, i was trying outlook , and thunderbird bla bla , i dont know why!
so as i saw when i had a look at the setting page for the pop3 in msgplus! i found you need to set the port, and this is same as configuring outlook etc.
so i dont know! i may be wrong!! i tried to answer , coz it was like u still had no replies since months!! so i wish i was helpfull, and wish someone will also help both of us in this issue!
Best regards