I’ve never used the WDSc editors (more the SEU type lol), but as no one has answered I would start by looking to see what server is being utilized on the System i to provide the source to the editor. Once the server is identified then we should be able to associate an exit program with that server.
The ‘DDM/DRDA request access’ exit point is generally what would be useful. Set it with:
CHGNETA DDMACC( mylib/myexitpgm )