[NTG-context] can typesetbuffer use the same engine?

Hello brain trust, How can \typesetbuffer be instructed to use the same engine as the document which contains it? With the following example: \startbuffer[Buffer]   \startTEXpage \contextmark \stopTEXpage \stopbuffer \starttext   \contextmark\   \typesetbuffer[Buffer] \stoptext I get "MKIV LMTX" when it is processed with context --luatex. I want the buffer to be processed as MkIV. -- Rik