Mac OS X Lion support is ready in version 1.2.8. You can upgrade from Appstore.
1. Tap on the blue arrow on each server entry, server setting page will show up
2. Turn ON "Mac OS X Login"
3. Input your Mac username and password which you use to login to the Mac. You should be able to login.
To get your Mac username, on your Mac, go to Applications->Utility->Terminal, type whoami, then press Enter key, your username will be shown.