On a trainer the rudder does cause the aircraft to roll as well as yaw. I think that is the one you were looking for. It is so bad that you have to use just as much opposite aileron as you do rudder just to keep the wings level during a turn.

A good place to start is to use the rudder on the ground, then use ailerons and elevator for turns in the air. This will be enough till you get the orientation thing down, and get some simple aerobatics under your belt. (Loops and rolls.) I would start with figure 8's where you turn right on your right side and left on your left side. Only problem with these turns is that you will not be lining up with the runway. After you get used to this then switch to right turns on the left side and left turns on the right side. After you get used to this start working the airplane over to line up with the runway as the nose passes by the ends of the runway, (high overhead ofcourse).

After you get used to these exercises you may want to start working in rudder, and then try rudder turns keeping the wings level.