Arc 15inch Deep Dish Wheels. Center Caps??? Info??

I got a set of Arc alloy wheels. I went on their site and couldnt find any details about them. Heres a link to what they look like.

ARC Alurad Dish Alloys.

160mm across the center cap

I think they need a 56mm inner diameter with a metal ring to press the clips out a bit so it grabs the alloy center when pushed on. Or a 4x100 pattern that grabs the nuts on the back. Anyone know a Vag bit that works or has the 160 diameter face?

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=200100984126

The guy did hand craft a set of caps to seal on but there nothing like kit that fits. (turned out to be really nice castellette alloy centers (rivage ish)Anyone able to tell me what these alloy where fitted on originally. Thanks.