The problem is I have a wall behind me so I can't move them a short distance behind the listening position.

This is from the FAQ page:

Where should I place my surround speakers?
Ideally, surround speakers should be either wall-mounted or stand-mounted to either side of the couch or primary listening area, from one to six feet higher than seated listeners' ears, and slightly forward or rearwards of the listening area if you wish.


Also this link http://www.axiomaudio.com/5.1DolbySurroundSystem.html
depicts the surrounds being forward of the listening position. But it assumes there isn't a wall up against the sofa. So I'm asking if it's ok to move the QS8's perpendicular to the rear wall almost touching it to get the rear effect in this circumstance without sacrificing performance?