Hi Asbath,
1.) the code you have sent looks like there is a blank between # and date_actu. There should be no blank.
2.) You use the method selectAllSortBy: and not sortBy:
I tried your code with my classes (with mongodb) and works like this:
RKAPerson selectAllSortBy: {#date_actu-> 1. #heure_actu-> 1} asDictionary.
This works for me.
I hope this helps.
Sabine