740 headliner removal problem

I am replacing the headliner in my '86 Volvo 740 Turbo.

Sunroof itself is out, now trying to remove the headliner / pad from
its position in the sliding groove.

Problem: how to get it out?

In particular, there are two appendages on the side, toward the front
(they have plastic on the outside) which ride in the groove; I can't
for the life of me figure out how to remove these from the groove.

 

It's tough, there's some notches at one end where it can come out, but
you can't really see them with it in. What I ended up doing is removing
the entire sunroof assembly, it's held in by screws around the perimeter
of the pan. Get help for this and make sure you use the right screws
when putting it back together. The headliner is an enormous project,
especially on a sedan.