I use BT Home Hub with Hub Phone but I haven't got broadband talk. When I want to register BT is trying to get me to buy Total broadband which I already have.
I use this site when i try to register.
I asking for help.
(sorry for my language)
I had the same problem, you cannot do it online. I ended up ringing them to register for the service, after that it went smoothly.
Ring 01234 567762