Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Encapsulated
ID_CA_XREFADD_ENCAPSULATED
Parameter: Generator
ID_CA_XREFADD_GENERATOR
Parameter: Name Space
ID_CA_XREFADD_NAMESPACE
Parameter: Auto Match
ID_CA_XREFADD_NAMESPACE_AUTO
Parameter: Prefix
ID_CA_XREFADD_PREFIX
Parameter: Separator
ID_CA_XREFADD_NAMESPACE_SEP
Parameter: Animation
ID_CA_XREFADD_ANIM
Parameter: Frame
ID_CA_XREFADD_ANIM_FRAME
Parameter: Offset
ID_CA_XREFADD_ANIM_OFFSET
Parameter: Scale
ID_CA_XREFADD_ANIM_SCALE
Parameter: Materials
ID_CA_XREFADD_MATERIALS
Parameter: Point Cache
ID_CA_XREFADD_POINTCACHE
Parameter: Hierarchy
ID_CA_XREFADD_HIERARCHY
Parameter: Transform
ID_CA_XREFADD_PSR
Parameter: Mode
ID_CA_XREFADD_PSR_MODE
Parameter: Parameters
ID_CA_XREFADD_PARAMETERS
Parameter: Mode
ID_CA_XREFADD_PARAMETERS_MODE
Parameter: User Data
ID_CA_XREFADD_USERDATA
Parameter: Mode
ID_CA_XREFADD_USERDATA_MODE
Parameter: Points
ID_CA_XREFADD_POINTS
Parameter: Mode
ID_CA_XREFADD_POINTS_MODE
Parameter: Relative to Project
ID_CA_XREFADD_RELATIVE
Parameter: Incremental
ID_CA_XREFADD_INCREMENTAL
Parameter: Position
ID_CA_XREFADD_PIVOT_POS
Parameter: Scale
ID_CA_XREFADD_PIVOT_SCL
Parameter: Rotation
ID_CA_XREFADD_PIVOT_ROT