I think this is what you are looking for:
C:\Users\[username]\AppData\Roaming\Adobe\Dreamweaver [version]\en_US\Configuration\Shared\WebAssist\CSSMenuWriter\presets
(at least if you're on Windows)
If you are having trouble with the UI, we'd be happy to help. Feel free to start a new thread in that case so tech support can pick it up. Thanks!