When i start a rolling maul, i make sure the ball catcher has the circle flashing on him he is then the maul starter, bind as many players at the start so you have a good weight advantage, once you have started that the circle will automaticaly go to your srcum half, when you think you have a good bunch press left analogue stick to the left/right up/down depending on what camera angle you are using? and the direction you are playing, this should work as it does for me. . .
Scrums more or less the same thing but dont hook b4 u place the ball into the scrum! once the ball is in the scrum press the direction you are playing, but if your pack is not so strong then the srum will not move far or not at all. . . . .
This is the same for the PC as well as the PS2 but i play more on the PC. . . .