Campagnolo freewheel /hub query

I have some mavic ma2 with Campag Victory hubs. They currently have a 6 speed freewheel. I want to use the wheels on a another bike with chorus groupset which is either 7 or 8 speed.
What are my options -
Do I need to source a 7 or 8 speed Campag freewheel or is there another make of freewheel which will be compatible with my hubs.
Any ideas /advice are gratefully received
Thanks

It should say on the hub what the threading is: English/ISO: 1.370" x 24; Italian: 35mm x 24.

I didn't realise that freewheels came in different threadings...

http://sheldonbrown.com/freewheels.html
Everything you need to know in one handy place.
Check you're threading (Italian and English threading can generally take the same freewheel). French is a different story.
There are many different brands, I use a Regina at the moment with 7-speed record, but have used Atom before...

Thanks for the info