Ablefton:

This pic from this excellent tutorial was the one that helped me the most when I had a similar problem:

http://img262.imageshack.us/img262/5...4620zl3.th.jpg


look at the pins position (it has to be exact!) and look at the white plastic position, it has two endings with miniature round spots on top that must also be specific. It also help if you kind of push the brackets of the aluminum ring in a little so they fall in position when you slide the white plastic piece down unto it.

In addition, please notice, that the way the picture is taken and the way you may be assembling it is different, to me it was better to have the plastic piece on top and in the picture is on the bottom (ready to go back into its phone place.) I was not taking that into consideration when assembling the little pins...I hope this helps!