Audio via the new Digital AV adaptor with iPad2

We just got our hands on an iPad 2 and immediately tested it with the Digital AV Adaptor we had bought. We connected the adaptor to a HDMI cable and then plugged the HDMI cable into the console we have for our data projection system.
We were very pleased to see that the iPad2 was recognised immediately and mirrored to the projection screen. This will be really useful for teachers in schools who want to project from the iPad. A selection of Apps we tried all mirrored successfully.
The only problem we encountered was with audio from one of our book apps. Supposedly the AV digital adaptor will ouptut the audio with no need for an audio cable. However it seems that there is a caveat. This below from the apple support page:

When mirroring*via HDMI with the Apple Digital AV Adapter, apps cannot simultaneously record and transmit audio. Since both iMovie and*GarageBand feature audio recording capabilities, audio transmission over HDMI is disabled. Audio*can continue to be monitored through the*stereo headphone jack or iPad built-in speaker.

So what this means is that if you are projecting from any any book app or other app like Garage Band that has the capability to record you may need to plug in an audio cable into the headphone jack of the iPad to hear the sound. See previous post for more details about the adaptor.