Guitar Tracks Pro 4 menu option (not there?)

Hi,
 
I'm a long time user of GT2 and just upgraded to GT4 pro. I seem to be having a newbee problem: I cannot see the Process-AUDIO option in my menu when I select part (or all of a clip), or therefore any sub options under the AUDIO. It's not even grayed out, it's just not there.
 
I assume that I've forgotten something, but I'd sure like some help.
 
Rob
 
(using Windows XP Media Center)