Well, a pictures worth a thousand words, but that picture doesn't show much... (sorry way too dark)
That aside I own a couple Antec TP 650watt supplies; they come with the correct connectors for a crossfire setup:
2 x 6-Pin, 2 x 6+2-Pin
Just use one 6 pin & one 6+2 pin per card.
I've got 5770's running in crossfire in my rig no issues with connections...........
NOTE: that 650watt is a good supply and this site recommends a 600watt supply for CrossFire so size SB goodhttp://www.realhardtechx.com/index_archivos/Page362.htm