The TAPICLIENT_LineSetCallTreatment function is called during a call to the lineSetCallTreatment function.
LONG TAPICLIENT_LineSetCallTreatment(
HMANAGEMENTCLIENT hmClient,
LPTAPIPERMANENTID lpPermanentID,
DWORD dwCallTreatment
);
lineSetCallTreatment, TAPICLIENT_ClientInitialize, TAPIPERMANENTID