In order to access Backup Assistant for the secondary line on the account, you will have to register the secondary line on the account as logging into the primary account will only display the contacts for the primary line. You are able to access registration through the following link:
Once the registration process is completed, you will then be able to access the contacts for your line.
I tried this process but it did'nt work in my Droid X, what's the problem? Yes,main phone is working good but the second line is not.