MUST be spray glue capable of withstanding high temperatures. i.e. 70
degrees Celsius.  50 degrees Celsius is not good enough.

In the UK, the most respected supplier of glue and material  is Woolies.

www.woolies-trim.co.uk
+441778347347

I used them, ran out of the glue and I tried finishing off with some super
strong spray glue from a motor factors. It wasn't nearly as good as the
woolies glue.

Al

Try http://www.wlsheadliners.com/ I've used them before.

I re-did my 900 about two years ago, it came out quite well and has held up. I
used 3M "super trim" aerosol adhesive, and headliner material I bought from
http://www.interior-supply.com/audoheadlining.shtml.

If your car is a four-door (non-hatchback) like mine is, getting the headliner
shell out of the car (without removing any glass) is really tough, but possible
if you take out the front seats (and maybe the gearshift lever) and are
patient.

Some URLs I found informative:

http://www.interior-supply.com/autoheadlining.shtml

http://www.saabnet.com/tsn/faq/liner.html

John