@ Cheers...
I'm in Australia as well and before I bought the unit I contacted AD support regarding the microphone issues. Here's a quote of their email:
"For the microphone Inputs you can get Impend. Matcher Adapter which will solve Problems with the microphones.
Headphones Problems are mostly stuff that comes by the headphones you are using. A lot of headphones are to high
in its impend. !
I hope this will be a little help for you !"
It seems you can buy this Impedance Matcher Adapter at any Music Equipment Store although I haven't bothered looking for one yet as I don't have a mic.
Hope this helps.
Cheers Mate