You really need qSortCriterias, which is not included in the dimension info in the layout (that might be considered a bug). When you turn off sorting in the standard property panel, the client will still set qSortByLoadOrder to 1, like this:
So QIX engine still thinks its sorted (which it is..).
A workaround would be getting the properties and checking qSortCriterias.
Hope this helps