I use this code (small part of it):

CompoundPath([group]);

group.clipped = true;
group.clipMask = true;

After the code is runned then it looks like this in the layer panel:
http://img338.imageshack.us/img338/5617/schermafbeelding2010041n.png

However the mask doesn't work yet, in order to make it to work i have to press the 'Make/Release Clipping Mask' button 3 times.

This is how it looks after pressing 1 time
http://img217.imageshack.us/img217/2337/schermafbeelding2010041d.png

after 2
http://img714.imageshack.us/img714/3408/schermafbeelding2010041z.png

after 3 times, this is how i want it
http://img714.imageshack.us/img714/3163/schermafbeelding2010041v.png

How can i archieve this?