Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Color
CLOUDSHADER_COLORParameter: U Frequency
CLOUDSHADER_SCALEXParameter: V Frequency
CLOUDSHADER_SCALEYParameter: Level
CLOUDSHADER_LEVELParameter: Compatibility Mode
CLOUDSHADER_COMPATIBILITY