I went shopping at Radio Shack for parts to run mine off of the power supply.
One roll of 2 conductor wire (black and red), and a mini plug/socket (like a headphone plug-in with it's matching socket).
Remove one back bracket cover from the case that wasn't being used, drilled a hole in it to fit the socket's threaded end.
Solder wire to the socket's connectors, and to the cut/stripped end of the 12 volt plug from the power supply (the square one with two yellow and two black).
Measure wire that's as long as your tubing, and cut it. This one solders to the mini plug at one end, and the stripped fan wires at the other.
Now my wire is removable from the case incase I wish to move it, and my panaflo fan has a plug on it to move the heatercore if I need to. It's powered by the power supply, so it's always on when it needs to be.
Use electronic solder and flux, not plumbing solder or flux. You can get that and an iron at radio shack while you're there.
You MUST put the outside collar as negative, and the inside conductor (center pin) as positive for this, as it grounds to the case, and would keep your system from booting if it were reversed.