Here's a place that stocks left hand metric taps and dies, not sure if it's the pitch you need. Your best bet would be to pick up a metric thread pitch gauge and check the thread on your gun. Anyways here's the link
http://mdmetric.com/prod/widell/LH.tap.die.htm
EDIT: Here's another one but you have to contact them as they don't have an online catalog!
http://www.tapcousa.com/default.asp