2003 BMW 540i sunroof

2003 BMW 540i

have the sunroof off, and all but two of the broken parts off. How do you remove the shuttle piece that is connected to the cable (the one that actually moves the glass) there are two cut outs in the rail, and on slot at the front end. The shuttle piece is somehow fixed to the cable, and I cannot figure out how to get this part off.
I do have parts on order, and maybe it will have directions?

I don't want to take the headliner and the whole "cassette" off to do this. Son't think I have to, but not sure.
Thanks.