Boost for SQL - single lockbox guide?

Using Boost for SQL version 3.5 has been great performance-wise, but we have too many SQL servers to store a lockbox on each server. The install and admin guide shows an option for storing a single lockbox (guessing on a share - doesn't say). Does anyone know how to do this, either through the GUI or using "msagentadmin.exe administration" commands? Solving this would make my DBAs VERY happy.

Thanks!