Validar RFC en Windev

PROCEDURE ValidaRFC(tcRfc is ANSI string):boolean
IF MatchRegularExpression(tcRfc, "[A-ZÑ&]{3,4}[0-9]{2}[0-1][0-9][0-3][0-9][A-Z,0-9][A-Z,0-9][0-9A]") = True THEN
RESULT DateValid(StringToDate(Middle(tcRfc,Length(tcRfc)-8,6),"YYMMDD"))
END
RESULT False