The ServiceEntry entry point is called by MAPI when the user configures the provider by means of the system's control panel applet. The ServiceEntry entry point is called after MAPI has gotten new configuration information from the user. The ServiceEntry entry point needs to incorporate that information into the hook provider's profile section.
The ServiceEntry entry point is passed a window handle it can use as the parent window for any user interface it needs to display. Usually the ServiceEntry entry point only needs to display a user interface to confirm or correct any bad configuration information entered by the user. In addition, the ServiceEntry entry point is passed pointers to memory allocation routines and a MAPI support object that can be used to access the hook provider's profile section.
For more details, see MSGSERVICEENTRY, and Supporting Message Service Configuration and File Format of MAPISVC.INF.