Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Rendered
VP_TEXT_RENDER_OUTPUT_RENDERParameter: VideoPost
VP_TEXT_RENDER_OUTPUT_VIDEOPOSTParameter: MultiPass
VP_TEXT_RENDER_OUTPUT_MULTIPASSParameter: Title
VP_TEXT_STRINGParameter: U
VP_TEXT_UParameter: V
VP_TEXT_VParameter: Tab Size
VP_TEXT_TAB_SIZEParameter: Align
VP_TEXT_ALIGNParameter: Align
VP_TEXT_INFO_ALIGNParameter: Objects
VP_TEXT_INFO_OBJECTCOUNTParameter: Lights
VP_TEXT_INFO_LIGHTCOUNTParameter: Polygons
VP_TEXT_INFO_POLYGONCOUNTParameter: Vertices
VP_TEXT_INFO_VERTEXCOUNTParameter: Render Time
VP_TEXT_INFO_SCENETIMEParameter: Color
VP_TEXT_PENParameter: Opacity
VP_TEXT_PEN_OPACITYParameter: Color
VP_TEXT_PAPERParameter: Opacity
VP_TEXT_PAPER_OPACITYParameter: Border Offset
VP_TEXT_PAPER_BORDERParameter: Rounding
VP_TEXT_PAPER_ROUNDINGParameter: Draw Border
VP_TEXT_PAPER_DRAW_BORDERParameter: Image
VP_TEXT_WATERMARKParameter: Opacity
VP_TEXT_WATERMARK_OPACITYParameter: Scale
VP_TEXT_WATERMARK_SCALEParameter: Vertical Alignment
VP_TEXT_WATERMARK_V_ALIGNParameter: Horizontal Alignment
VP_TEXT_WATERMARK_H_ALIGN