Just a few tips - you need to manually add the table background image to the HTML code to make it look exactly like the vB3 mod cp login.
Also, you need to remove the username from the login text input box.
Ensure you remove all the vB3 <form> and hidden input variables, and replace it with the vB2 ones as well as the PHP code needed in the middle of the HTML code - his instructions don't make it clear.
As the hack author has stated he will support this hack, I will leave the rest to him.