There are a couple good threads in the forums regarding how to configure BIS 2.0 and gmail, as well as the pros and cons for 2.0 vs. 1.8.
I use it with three IMAP accounts, and I'm very happy with things. Each account you configure sets a reply to email address. You can also specify one for the
default.
If you want to see the advanced configuration settings when you create a new account, put in bogus information. You'll then be taken to a screen where you can configure everything manually. Necessary if you want to use POPS or IMAPS.