Mine's like that, except on the side it has an extra four pin socket that doesn't even have any wires going into it. I expected it'd detach, but it's one piece of plastic.
I'll check my PSU box to see if there's another cable I could use.
This PSU right? - http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=235
It does say it has a 8pin EPS or 4+4pin ATX that you can use.