Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Set
HAIR_SELECTION_TAG_SETParameter: Restore
HAIR_SELECTION_TAG_RESTOREParameter: Select
HAIR_SELECTION_TAG_SELECTParameter: Deselect
HAIR_SELECTION_TAG_DESELECTParameter: Lock
HAIR_SELECTION_TAG_LOCKParameter: Unlock
HAIR_SELECTION_TAG_UNLOCKParameter: Hide
HAIR_SELECTION_TAG_HIDEParameter: Show
HAIR_SELECTION_TAG_SHOW