[NTG-context] Import a metapost extension

Hello Is it possible to import a metapost extension into a file compiled with the lmtx engine ? I tried unsuccessfully with this example : %%%% begin test.tex \starttext \startMPcode input mp-scratch; Scratchversion:=3; draw Drapeau; draw Repeter("4"); draw Avancer("50"); draw Tournerd("90"); draw FinBlocRepeter; \stopMPcode \stoptext %%%% end test.tex Thanks Fabrice