Hmm..ok I hope this will be a feature for the next eZ to come.
Workaround: Is it possible to force eZ to create an object as another user? So instead of user x (logged in) it will use user y (user that can post without approval) as creator of object?
First create an approval workflow in which you specify the editor and possible users/groups who do not need approval.
Second create a multiplexer workflow with a single multiplexer event in which you sepcify sections (if any), classes (that's where you limit which classes need the approve workflow, the others don't). Leave the users without workflow as it is (none selected) and choose the approval you created before.
Third: attach the multiplexer workflow to your publish trigger.