PX350 USB Help ?

I have loaded my USB pen with a whole load of Midi files we use live.
Calling them up is easy enough, but how do I come out of USB mode ie having all the PX350 functions available to me at the touch of a button ?
Pressing the Audio Recorder button seems to allow me to come out of midi file mode and allows me to select tones etc and play along, but I cannot access the Function button and for instance transpose a tone.
The only way seems to pull the USB pen out, surely there is another way ?

Ok note to self "Read the manual" its always a good start !

Press function whilst holding Audio Rec.
Then to bring the function button back on-line press Accom on/off button.

Sorry I didn't get to your post sooner. Enjoy your PX-350!

Thanks Mike..Im Loving it.
One thing though ? I have a lot of MP3 backing tracks to.
I have converted these back into Wav format at 44100 and 16 bit using Audacity as it would appear that the PX350 can play Wav format audio files.
However the PX350 says "no file" I have loaded some trial wav files into Audio/Musiclib/and into the four sub folders in Play.
What am I doing wrong ? Or is it that the PX350 cant play wav files as backing tracks , rather just record in wav format ?

Many thanks

Mark.

They have to be renamed, to TAKE01.wav, TAKE02.wav ...etc.

Thanks for that Mike.
All hunky dory now.