I have tried all weekend to get my Dolby flag to light up on my 555ES. Apparently my amp will only send Dolby Pro Logic to the speakers and I am wondering if I have to access the coding through the 5.1 Inputs on the rear of the amp (from my Sony DVD Player) rather than Toslink Optical...or maybe my receiver is just broken

Have been looking through the manual and dinking around all weekend after getting my Kef iq8ds' up. Any help would be greatly appreciated!
conga