Have you got ASIP working on the same machine as OS X Beta? I'm using ASIP for my mail server and would love to run it on the same machine as OS X Beta. But, it crashes the classic environment whenever I launch it.
I'm not sure of a software solution, but I'm running an AirPort network with an AirPort hub. Although OS X Beta isn't AirPort ready, that doesn't stop me from using the wired version from my Beige G3 tower with OS X, and my iBook still runs wireless with OS 9. Of course, this doesn't sound like it would really solve your dillema. I'm sure there are answers under the hood of OS X Beta if you are or can find a Unix critter to implement it.