Me and Renegade just got Rank 8 Veteran Status from EA support, basically make a Battle Field Bad Company 2 Account on your Xbox, goto this site and sign in with the email and password you used to make the profile on the game. http://support.ea.com/app/ask, click on live support and choose the following.
Product: Battle Field Bad Company 2 Obviously lol
Platform: Xbox 360.
Sub Cat: Promotional Offers.
In the question box me and Renegade just typed
"Hi there, i just recentally bought battle field bad company 2, i love the battle field series and have for many years, i noticed with this amazing game the veteran status on the website, but unfortunatly every time i try to enter my Battle field Vienam product key the website gives me an error, could you help me please?"
Then they tell you to wait a few mins, they ask you your email and date of birth, wait a few more and then you recive a link to your profile with rank 8 Vet, hope this helps.