[Asterisk-Users] Analog extensions behind E1, how to create them?

[Denis Galvão - iSolve]

I will have some extensions behind an E1. All of them will need the  
features/applications of Asterisk.

Analog Extensions <-> PABX E1 <-> E1 Asterisk IP <-> VoIP trunk
                                         ^
                                         |
                                         |
                                     IP Phones

How is the best way to create this users on Asterisk? Some of them  
will have a SIP account to have its extensions with mobile  
functionality when they will be out of office, others will not have  
this feature.

Some examples will be great!

Thanks.

Denis.