Sharepoint 2010 publishing via ISA 2006

I'm in the process of setting up a Sharepoint server which will be accessible via our ISA server.

Now, can anyone give me any clues as to how I do this? I've tried the basics - setting up a listener on port 80 listening for a certain domain, with forms based authentication.

I've then done a simple sharepoint publishing rule, using that listener.

I've then gone into the Sharepoint 2010 Central admin site, and set up an 'Alternate Access Mapping' to point the internet zone at the external domain name.

Yet it refuses to work. Doing a 'Test Rule' in ISA returns a list of errors '400 Bad Request' etc...

I'm not working with SSL as yet, as I just want to make sure it actually can and will work first.

*bumpus*

Having never done it before I'm not sure but things that I would check for are:
If the listener/rule rewrites the traffic headers to make it look like internal traffic or leaves it as external.
If the authentication passthrough type is supported, I know that passthrough of Exchange 2003 forms based credentials needed to be set as basic or NTLM authentication on the internal server for it to be passed correctly.
If the server can resolve the right way to get the traffic back out.