Mini display port cable and Thunderbolt cable compatibility

I need to run a Mini DisplayPort cable from a last generation Xserve to a circa late 2010 iMac so I can directly share the iMac's display while I set up the Xserve.

Apple no longer carries Mini DisplayPort cables at their stores here in NY. No one at the store could tell me if I could use a Thunderbolt cable with the hardware I have.

So, a hopefully simple backwards compatibility question: Can I use a Thunderbolt cable to connect the Mini DisplayPort of the Xserve to the Mini DisplayPort of the iMac?

According to this source, you will not be able to use a Thunderbolt cable in this fashion.

You can, however, get a Mini DisplayPort to Mini DisplayPort cable from Monoprice for about $5 and that should work just fine.