How can i setup and provision remote extensions on sipura or linksys device

I have [email protected] and i want to know how to provision my 4 boxes located in london, Phoenix arizona, Hlendale arizona and california.
My asterisk is located here in phoenix and i have a local address of 192.168.1.107 as its ip address.
Second question is, how can i set it up so that i see the ip addresses or mac addresses of these remote boxes in order to configure them.The boxes are SPA 2100 and 1 linksys PAP2 NA