This method worked for me except for step3(reboot into RUU and Silver HTC Logo WITHOUT green progress bar). so im gonna share my workaround:
1. Do step1 and step2.
2. copy rom.zip to SDCard(root). rename to PG86IMG.zip.
3. Relock Device
4. Go To Bootloader and let system find PG86IMG.zip. 'Yes' when asked to update.
Now, you will see lists of things to be updated - mine stopped @ No. 7. the important thing is No. 2(Boot) - it should show 'OK'. if you encounter this, just press Power button and verify if you have Hboot 1.49.0007. (mine was even unlocked, don't know why).
5. Continue on to Revolution and Enjoy.
6. Thank Flashmaniac for the tool and s_superman for the original thread where this was first found