If this isnt ok delete as necessary but please check out tekguru.co.uk as we have a good XDA II community there which will answer any of your questions...
You wont be able to use any of the standard cf card type extenders because the XDA II doesnt have a CF slot unless you have the backpack (still unavailable AFAIK) which includes a CF slot but isnt pretty.
What you can do though is buy total remote 2 which comes with an extender which plugs into the headphone socket. Though its obviously not perfect with the XDA II because the headphone socket is at the bottom. The new total remote software now supports CCF files and is available here including the IR extender.