looking at the DIY again..

When the caliper is in this position you can compress the piston much better.

http://tinypic.com/mbl3qr.jpg

compress like this.

http://tinypic.com/mbl6w9.jpg

considering that you have been following that DIY guide. and still having problems.

The problem could be that you just need to move the caliper foward and back ward to jiggle it back into position.