Line Buttons on Polycom SP 501

Okay so I am beating my head.

The polycom 501 have three line keys. All I want to do is get key one and two to display the same extension, and use the third to log in dynamic users. I have already set up users and devices instead of extensions, but it seems that I have to create a new device per line key? other wise the endpoint manager will not let me use more than one line key. Should I have to modify the template?

There is a setting in the line registration for number of keys. Just use a speed dial for the queue login.