That depends... how do you get remote phones working? Do you have an MiVoice Border Gateway or just using port forwarding/DMZ to the MiVO250? And how trainable are your users?
Best case scenario, put the MiVO250 in a data center or hosting site and have all phones be Teleworkers to that. Then it wouldn't matter where they are, in the office, at home, on the road, etc. All phones would be Teleworkers in NAT mode.
Second choice, you have an MBG and trainable users... Users could take their phones home, place them in Teleworker mode and point them to the MBG. The MiVO250 doesn't need any changes.
Worst case scenario, you are doing simple port forwarding and would need to due 2 things. First, in the system configuration of each user change their NAT Type from Native to NAT -AND- have each user place their phones in Teleworker mode.
There are other options, depending on the number of people we are talking about... Can you give us a better scope? And are you willing to change phones?