[NTG-context] Start of application within a context document

Hi, If you excuse my ignorance, but I am looking for a simple example how to launch an executable (a tcl/tk script in my case) from within a pdf document prepared by context. During a presentation i would like to show some graphics which are generated through the execution of a tcl/tk script. One could close the pdf file and open the tcl/tk script, but it would be nice if one could symbolically link the script within the pdf file. Because I prepare the pdf file using context, I searched the context manuals, but didnot find a solution to this problem. Therefore if somebody has solved this already and is willing to share his/her experience I would be grateful Thanks Stephen