"Bricked" my HTC touch Diamond - HELP!!

A couple of weeks ago I was flicking through various cooked ROMs on XDAdevelopers and after trying out several windows mobile versions, I happened to turn my HTC Diamond into a luxury piece of furniture.

Well, it turned out that I flashed a wrong version of ROM (intended for CDMAs) into my GSM phone.

My phone switches on normally, but it freezes on the Diamond logo and doesn't go any further (as above).

I tried all sorts of hard reset options and I hard-reset it many times by pressing different keys, however it still freezes on the Touch Diamond logo at the start-up after a brief vibration.

Simply put it, when connected to usb port, it only starts charging and the circular lighting starts flashing but obviously my pc doesn't detect anything being attached to it.

As the warranty is still valid for 5 months, I posted it to the HTC service centre and surprisingly enough they invoiced me for £280 as "the fault is caused by unauthorised software update".

Well obviously I gave up on the whole repair thing and my phone was returned to me intact.

I've been searching many places for a possible solution and so far the only reasonable idea is 'JTAG'ing the NAND chip which needs some soldering, a cable and some software to flash an original ROM directly onto it. I'll be grateful to anyone who can refer me to a possible solution.