There's absolutely bugger all in the way of decent manuals for GasGas's. Saying that, they're pretty simple beasts to work on. I stripped mine down making sure I had my cameraphone handy and took pictures of everything as it came off. Have a nice, clean workspace to lay things out on and you shouldn't find it too difficult.
the official gasgas website does have exploded diagrams for download, but they're not really that much help.