When you compile the custom adapter configurator and make it available in the OpenEdge Business Process Server classpath (see
Compiling and packaging the Adapter classes), you must change the mapping.prop file to list the adapter configurator class before using it in Progress Developer Studio for OpenEdge.
This will make the adapter configurator available from Progress Developer Studio for OpenEdge.
Note that in case you have an already existing application using the MathAdapter, this change will not be automatically propagated to the worksteps in this application. You will have to change the configuration (Workstep Properties dialog > Configuration > Advanced Properties...) and republish the affected applications.