[NTG-context] Using spotcolors in TikZ

Hello list I want to use spotcolors in a tikz-picture. Is this implemented? I get an error: Package pgf Error: Color test_line has an unsupported color model. MWE: (does not work) \usemodule[tikz] \setupcolors[rgb=no,cmyk=yes,spot=yes,state=start,overprint=yes] \definecolor[PantoneTwoNineFour][c=1,m=.56,y=0,k=.18] \definespotcolor[test_line][PantoneTwoNineFour][p=1] \definespotcolor[test_fill][PantoneTwoNineFour][p=0.5] \tikzset{mybox/.style={rectangle,rounded corners,align=center,thick,draw=test_line,fill=test_fill}} \starttext \starttikzpicture \node[mybox] at (0,0) {Test}; \stoptikzpicture \stoptext Thanks for helping me. Christian