I drilled some holes into the case on one side and mounted it on a g-snap there. Just behind where the wing sits.
You need to be careful any bolts cannot foul the counterlungs though. I am going to cover my bolts with a plastic cap but to be honest they are so short there isn't a problem.
Some interesting alternatives here:
http://www.yorkshire-divers.co.uk/fo...ighlight=argon
Jamie