The following mod allows you to use a standard Xbox 360 cable to create a special VGA cable that would normally be purchased separately. The reason we can hack the standard cable in this way is ...

VGA to RCA cables don't work for 99% of devices. Are you positive that the card can output the composite video signal?

Not likely - the video chip has to know that it needs to produce NTSC signals - basically this is something done on the second head of say a Matrox card or the ATI/NVidia setups that Dell uses ...