Rizla:
Question: does the power switch function normal for switching
ON?
If yes, I suggest to do that:
Update your reader with a newer custom build of PRS+ (you could make it yourself or could grasp it there:
http://erhartc.bplaced.net/ereader/).
Assign in PRS+ options a custom user gesture (say a down swipe) to go into sleep mode.
So you need the power button just for switching the reader ON, not for switching it OFF.
A.