I had to fix this myself on my old VS.
From memory, Street Commodores' forums have a very useful step-by-step sticky thread for this in their DIY VS section.
In essence though:
1. Pull away plastic stanchions along roof lining
2. Carefully take out roof lining (it will be a semi-hard cardboard mould) - you will need to re-use this
3. Peel off material
4. Get a scraper and scrap away foam and glue material, try not to damage the cardboard
5. Go to spotlight and purchase desired material, go to Clarke rubber and purchase 5mm width foam, go to Bunnings and purchase Apoxy glue
6. Cover glue on cardboard
7. Place foam onto glue
8. Leave to dry
9. Trim with knife
10. Cover foam with glue
11. Cover glue with material
12. Fold excess around to other side of cardboard and staple, cut V shapes where necessary for neat trim
13. Leave to dry
14. Reinstall
15. Clip in plastic stanchions
16. Done
In regards to the cardboard frame - I believe you mean the roof-lining, you will need to re-use the one you pulled out. Clean off the old glue and foam and material ready to apply new glue and foam and material. If you broke it, or it isn't re-usable, you will need to visit your local wreckers for a new one I would presume. Rip it out of a trashed one.
