Paul,
If the soundtrack is PCM then you can configure the 568 to DPL II and it will do it with no problem. If the soundtrack is DD 2.0 the 568 cannot do both, decode DD and DPL II. I believe that you can set the 598 output to PCM when encountering DD 2.0 and the 568.1 will then decode DPL II from a DD 2.0 soundtrack, because it (568.1) will see it as a PCM signal. I have a 596/568 combo with 2 user types, one called movie, one called music. For the DVD source (PCM) in movie type, I have DPL II MOVIE set as default, and for the music type, I have DPL II MUSIC set as default for PCM signals. I have these 2 types because I have different crossover/gain settings for the subwoffer.
Steve