you dont have to go through the trial account rubbish.
you can simply set it up as you would a normal startup

create new Battlenet account:
activate the first vanilla install from purchased code
send out the five raf links from this account (if you want them all inked to this account)
click on the referral link in the email and setup the account putting in the purchased vanilla codes when prompted

(if have found from prior experience its easier picking up battlechests than the hassle of digital downloads and the wonderful #203 error )