Angelo is correct. The other H/K models do not support Dolby Digital EX in any way, shape or form. Previously, EX was only available with a full THX license. Dolby changed this at some point, but it was too late to add to these models.
You could, however, use the old trick of adding an old Pro-Logic receiver to the Left/Right pre-amp outs. Put the receiver in '3 Stereo' mode and voila! Pseudo EX.