Drobo

Drobo 810N - Remote DR set up

Can anyone provide me with a detailed instruction on how to set up 2 drobo 810n units for remote DR replication.
I have run the DR with the two units on the same network; now I have one unit at home, and other at the office; but I am lost as to what to do and how to have the office unit (source) be able to find the destination unit at home.
Thanks