Removing head of Inova T5

I have an Inova T5 that has died on me yet again and instead of sending it back in for warranty I'd like to take off the head and see if I can't throw in a Cree and new driver. Problem is that the damn thing won't come apart! I have tried strap wrenches, leather scrapes, leather belts, vices, heat guns, etc. but it won't budge. Any trick to this trade? It's not the new 2008 model I got it early last year if that makes any difference. My uncle suggested that I send it in with a letter asking them to not glue the thing closed as I won't be sending it in again anyway since this would be the second time and it's about $10 a pop at returns, would they honor that request? Thanks for any help.

I had a TIROS version of the T4 I was thinking of taking apart for an emitter swap, plus the optic had become loose and was rattling around. Various members pointed me to some threads for advice as to how to disassemble, but rather than attempt myself, I called Inova to address the issue. I was surprisingly told that the head is in a sense 'welded' onto the body. I can't verify this of course or go into specifics of our conversation as it's been a few months since we conversed and I honestly don't remember them. But rather, tto avoid the headache and elbow-grease, I did what you're trying to avoid and reluctantly sent it in + some $$ in trade for a newer version.

am not sure about those lights but others have used the freeze pop method on several Inova lights. Apparently they are press fitted in there and filling the light with water and freezing it in several stages will push the light apart.

I've taken the head off my T5 and can tell you that it's screwed on so the freeze pop method will not work.
There is "loctite" or some similar adhesive in the thread and mine was very difficult to remove. Some have reported success with heating but it seemed to make little difference to mine.
The main problem is protecting the body (bat tube) from score marks from where you clamp it. Masking tape was not adequate in my case and I damaged the surface of the tube.
I tried a strap wrench but found it useless.
I ended up using a 12 inch pipe wrench with 24 inches of 1 inch pipe as an extension of the handle.
I used the wrench on the head with the body in a vice. The extra 24 inches of "handle" gave the pipe wrench enough grunt (torque) to break the adhesive.
Once removed the head lets you get to the LED and it's easy to replace BUT the driver is impossible to get at due to the fact that it's under the LED heatsink which seems to have been put in using thermal shrinking.
Inova use (used?) the most fantastic construction techniques in some of their units.
From memory the drive current was 900ma.
EDIT:
By the way a CREE will not focus with the TRIOS optics and you'll also have to trim its base to get it to fit into the heatsink (assuming the driver is working).
Good luck.