I'm sad to say none of those work. Every time I try adding any resolution to the registry, windows starts and I can see the progress bar, but as soon as it loads the main GUI, the screen goes black and I get the message "no signal" from my TV. I can hear the OS starting in the background though. I don't get why this happens because I haven't actually changed the resolution to a potentially incompatible one yet, I've just added it to the registry, right? The annoying thing is that when it fails I can't get any picture back on the tv, even in safe mode, so I have to connect it to a proper pc monitor and set the resolution back to something the tv can handle.
Anyways, thanks a lot for trying to help guys, I really appreciate it! I'm done trying now as I've spent too many hours trying to make this work. I've had htpc's hooked up to this television with 4 different graphics cards (both Nvidia and ATI, both new and old) and ALL of them were able to give me a working 1:1 pixel resolution for this TV.
I hate to sound all sad and defeated but I will never, ever, even think about relying on an Intel graphics chip again. I chose the P5E VM HDMI specifically so I wouldn't have to buy a separate graphics card, and the Intel G35 chip has totally disappointed me, and wasted a lot of my time, and now also the money I'll have to spend buying a proper graphics card.
EDIT: And now it seems I'm really screwed because I can't get a picture on the tv even though I changed the resolution back to 1080x768!