Need a source for a cable

I need a special cable: 6 pin Firewire male on one end, and USB-B male on the other end, like the end that plugs into a printer. I have looked on EBay and found some conversion kits, but none seem to have exactly what I need. Any links or leads will be appreciated.
Thanks.

 

If you know the pinouts you can make em yourself. Any chance of that being the case? I've done it myself plenty of times, not all USB cables are standardized.

 

Nope.... no such luck. A friend has some music/recording equipment or something. I'm not really clear on what the device is, and all he told me was "USB; like a printer plug, on one end.... and regular firewire on the other end". I've done a little research and it seems as if such a beast doesn't exist, primarily because even if the cable did exist, it wouldn't work when the devices were plugged in. It has something to do with the nature of firewire vs. USB.... but I don't know.... I even called a major cable retailer/wholesaler and was told exactly the same thing, but there is a chance they're wrong (isn't there?).