Any help on the following problem would be appreciated...

We're making a number of enhancements to an existing system.

Some of our use cases call for the system to issue a "reminder" to a user at some point in the future.

The system we're enhancing already has workflow functionality which the developers are going to use to satisfy this requirement. However, these workflows have a number of system parameters that need to be set (priority, type, etc) in order to work and which aren't part of the original requirement.

These parameters are set on the back-end and as they aren't visible to a user haven't been included in any screen design documentation.

Where should these parameters be documented?