Original 2002 Sony double Din Stereo with Aux?

[Steveee-B]

Hi folks
I have just managed to get the Sony XA-300 Aux switch for my car stereo and I'm looking for some pointers or ideas.
Idealy I would like to run the wires from my stereo up inside my dash to the storage compartment and have the Aux Switch box in there. That way I can have the input wire from my phone in its holder on the windscreen going under the compartment lid and mostly hidden.
Has anyone else done this and if so, is it safe to put holes for the wires in the base of the storage compartment?
I'm guessing there is ducting for the windscreen heating at the back of it but how about underneith?

If this idea isn't really do-able I would be interested to know where other people have installed their Aux box's.

Is the USB socket on the Aux box powered i.e. if plugged into a phone would it charge it as well as passing music through it?

I'm also looking for a Square USB to Micro USB cable with a built in microphone lead (if such a thing exsists) so I could run my phones (HTC One X) hands free capabilities as this steroe doesnt have bluetooth obviously.

Thanks for and pointers or tips.

Steve