Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Encapsulated
ID_CA_XREFADD_ENCAPSULATEDParameter: Generator
ID_CA_XREFADD_GENERATORParameter: Name Space
ID_CA_XREFADD_NAMESPACEParameter: Auto Match
ID_CA_XREFADD_NAMESPACE_AUTOParameter: Prefix
ID_CA_XREFADD_PREFIXParameter: Separator
ID_CA_XREFADD_NAMESPACE_SEPParameter: Animation
ID_CA_XREFADD_ANIMParameter: Frame
ID_CA_XREFADD_ANIM_FRAMEParameter: Offset
ID_CA_XREFADD_ANIM_OFFSETParameter: Scale
ID_CA_XREFADD_ANIM_SCALEParameter: Materials
ID_CA_XREFADD_MATERIALSParameter: Point Cache
ID_CA_XREFADD_POINTCACHEParameter: Hierarchy
ID_CA_XREFADD_HIERARCHYParameter: Transform
ID_CA_XREFADD_PSRParameter: Mode
ID_CA_XREFADD_PSR_MODEParameter: Parameters
ID_CA_XREFADD_PARAMETERSParameter: Mode
ID_CA_XREFADD_PARAMETERS_MODEParameter: User Data
ID_CA_XREFADD_USERDATAParameter: Mode
ID_CA_XREFADD_USERDATA_MODEParameter: Points
ID_CA_XREFADD_POINTSParameter: Mode
ID_CA_XREFADD_POINTS_MODEParameter: Relative to Project
ID_CA_XREFADD_RELATIVEParameter: Incremental
ID_CA_XREFADD_INCREMENTALParameter: Position
ID_CA_XREFADD_PIVOT_POSParameter: Scale
ID_CA_XREFADD_PIVOT_SCLParameter: Rotation
ID_CA_XREFADD_PIVOT_ROT