Hi,
the Mezzmo Android app should detect the Chromecast Audio device just like a normal Chromecast as they both use the same APIs. It is possible that we may need to update the SDK used by the Android app to support the Audio Chromecast so we will investigate to see if this is the case. Can you please try going to the devices page in the Android app and press the refresh button on the action bar to see if the Chromecast Audio device is discovered?

We can also let you try version 2.0 of the android app to see if this discovers the Audio Chromecast, please send an email to support [at] conceiva [dot] com and we can add you to the beta group.