Rear Rack rails? needed??

[guitarpicker_ma]

I just bought a used QSC RMX850 and have it mounted in an SKB US RotoRack. The QSC's manual suggests using the rear rails to suport the back of the amp. Is this necessary, or will the front rails suffice to secure the amp?
This is my first experience owning a seperate mixer/power amp setup (I've traditionally used powered mixer heads), so all this rack stuff is kinda new to me.

Thanks.

[chuckocaster]

as long as you put it on the bottom it should be fine. all the systems i work on don't use rear rails, and we're talking some pretty stout amps.