transparent mail proxy in 4.5

obviously doesn’t work when sending/receiving to/from localhost. communication is not intercepted by avast at all.

is there any solution?

Sure, this is by design. It’s easy to change this behavior, though.
Please see here: http://forum.avast.com/index.php?board=2;action=display;threadid=8646;start=msg70997#msg70997

Cheers
Vlk