You can do what you want with it.  The point is to not ask for help when doing things beyond the scope of what we offer support for.

The Bad Gateway messages are cosmetic and they should be there no matter which IP you are using. They appear always when a CARP IP is brought up.

Wouldn't this be the same problem you run into when you try to impose CARP on a set of bridged interfaces?  Basically the deal is that CARP and proxyarp (or bridging) don't play nicely together.

@kikawala: I did not try 0.94.10, but I did not have any problems with 0.94.12 Known problem, colin is working on configuration sync.