This is just a bit of info on how to make the 2 program co-operate.
Apparently, Avast 9 Web Shield changed the way it operate compared to the previous version. After Updating from Avast 8 to 9, ALL my inet facing programs failed miserably to connect, and that includes Avast's own updater.
It seems that Avast Web Shield is redirecting all inet requests to itself. While Avast 8 does the same thing, Avast 9 is more thorough, which I assume is better protection (or not, depending the point of view). Meanwhile, Outpost in "Block Most" mode uses white list on which program can access which port, and that redirection needs to be included in the list.
So, if you're using Avast with Outpost, you need to allow all programs which you allowed to connect to the inet in Outpost to make outbound TCP connection to remote port 12080, or they won't connect to the inet. And you have to explicitly include Avast updater to the list ([Path to Avast Installation]\Setup\instup.exe), allowing it to make that same connection, or you won't be able to update Avast.
Just wish this kind of info is available when updating to Avast 9. Maybe it can be stickied somewhere and/or included to the FAQ.
Hope it helps