With Audiominutes you can record your own message that will be played when the mute button is pressed. This is how you do it:
Firstly, download the sound software Audacity from here: http://www.audacityteam.org/download/
Go to edit ->preferences -> device and set Recording channels to 1 (Mono), then, still in preferences, select the quality tab and select default sample rate at 11025 Hz and Default Sample Format to 16-bit.
OK, you are ready to record your message – why not add a jingle too? here is an example
When you are happy with the results, go to the file menu and select Export Audio -> Save as Type -> Other Uncompressed Files. If you click the Options button you should see settings RAW (Header-less) and Signed 16 bit PCM.
Export your file with the filename adjournment.M16 (this is the filename recognised by Audiominutes. Now all you need to do is move that file to the Audiominutes/customsounds folder on your tablet. If no file with that name is present in that folder Audiomintes will play the standard mute message. If your new file is in the right place, in the right format and is correctly named, then your new audio will play. Good luck