http://www.google.com/search?q=dualh...en-US:official
Apparently, from the looks of the above Google search for 'dualhead12go linux', there are a large number of threads and sites which refer to that device, drivers and other info.
I haven't browsed the results, but if you find some relevant info there and need some help implementing it, please just ask!
Also, have you checked the HCL (Hardware Compatibility List, see top of this page) ?? Maybe there's a review of the gadget in there.
Incidentally, there's another user here I know of using a splitter of some sort, I don't know the make/model, but here's the thread:
http://www.linuxquestions.org/questi...d.php?t=534348