ah shit.... there goes my next paycheck. If wonder if its like the PM Concept TSEE kit, which uses a CO2 shaped charged gas tank which does in the pistol grip.
EDIT: Erp well it appears theres "a large gas tank in the stock tube" apparnetly!
Also found additional information and pictures here:
http://www.gp-web.com/en/productspop.php?pid=923
.....*fapfapfap*