I've actually seen this done in pictures on the web. Unfortunately, I can't remember where.
In theory, this should work if you can get the bulb to fit. A halogen bulb almost certainly puts off more heat than a MH, so heat should not be an issue. I need need to stress that I haven't ever tried this, but this is how I would try it.
The thing you need to worry about is the strike voltage. MH ballasts pulse the bulb at about 1500 or so volts to "strike" the arc in the tube. The wiring in regular halogen fixtures is doubtfully rated for that. You may need to take the fixture apart and replace the 300 or 600 volt rated wire with 1000 volt wire, or slip extra insulation (silicon NOT PLASTIC air line hose will work, most likely) over the wires all the way back to the end holders.
BTW, what does "sive or wut not" mean?