Loads and registers an API Add-in.
| Parameter | Description | 
|---|---|
| register | File name of the Add-in DLL to be registered. If no absolute file name is specified, the file name is preceeded with system's current directory. | 
| registerModule | Register an API Module. The Settings must be available, then the services are created. | 
| unregister | Assembly file title of the Add-in to be de-registered. The file title is the one displayed in the API module dialog. (This is the name of the assembly without path and without the ending .dll) | 
| unregisterInternal | Assembly file title of the Add-in to be de-registered. When an error makes the unload impossible, the module is only deregistered. |