Testing VS2008, this is what happens when VA is disabled, or has never even been installed. So VA is simply doing the same thing, to be consistent with what normally happens in VB files.
Unfortunately I cannot see any way to change this in the IDE settings. This is the way Microsoft has decided VB.NET listboxes should work with Enter, its not something VA is affecting. Sadly it looks like you are going to need to get used to accepting the listboxes with a different key.