cgashlin01,
First of all I believe that the MP-104 is an FXO gateway and doesn't have any FXS ports on it so the only thing you can use it for is to put POTS lines or analog ports into it. The remote location would also have to have a VoIP phone there in order to take calls from the system through the MP-104.
There is already a guide by Inter-Tel, which has been updated by Mitel, on how to configure those, but I am sure that you will have to downgrade the firmware to get it to work properly; which is why we don't use them anymore. Go the Inter-Tel site TheEdge through your Mitel Login and get the old firmware and guide on how to set it up. It is kind of a pain as the downgrade doesn't always work and you can brick the stupid thing and have to wait for Sonus, the new manufacturer, to fix it and return it if it is under warranty.
If you can't find the guide or the firmware let us know and I will see what I can do about getting it for you.
Thanks,
TE