Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Mode
ID_CA_TAG_VS_MODEParameter: Add View
ID_CA_TAG_VS_ADD_VIEWParameter: Add Hotspot
ID_CA_TAG_VS_ADD_HOTSPOTParameter: Remove
ID_CA_TAG_VS_REMOVEParameter: Image
ID_CA_TAG_VS_IMAGE_NAMEParameter: Zoom
ID_CA_TAG_VS_ZOOMParameter: Left
ID_CA_TAG_VS_LEFTParameter: Top
ID_CA_TAG_VS_TOPParameter: Right
ID_CA_TAG_VS_RIGHTParameter: Bottom
ID_CA_TAG_VS_BOTTOMParameter: Color
ID_CA_TAG_VS_COLParameter: Transparency
ID_CA_TAG_VS_TRANSParameter: Highlight
ID_CA_TAG_VS_HIGHLIGHT_COLParameter: Transparency
ID_CA_TAG_VS_HIGHLIGHT_TRANSParameter: Selected
ID_CA_TAG_VS_SELECT_COLParameter: Transparency
ID_CA_TAG_VS_SELECT_TRANSParameter: Link
ID_CA_TAG_VS_LINKParameter: Action
ID_CA_TAG_VS_ACTIONParameter: Command
ID_CA_TAG_VS_COMMANDParameter: Script
ID_CA_TAG_VS_PYTHONParameter: Views
ID_CA_TAG_VS_VIEWParameter: Brush
ID_CA_TAG_VS_BRUSHParameter: Lasso
ID_CA_TAG_VS_LASSOParameter: Shape
ID_CA_TAG_VS_SHAPE