Embed Gnuplot commands in Lyx

[Jürgen Lange]

Hello,
I tried to embed Gnuplot commands in Lyx.
The necessary package is gnuplottex.
Because I use Miktex, I put \usepackage[miktex]{gnuplottex} in the  
Lyx-preamble.
With Tex-Code in Lyx-document \begin{gnuplot}[terminal=pdf] plot sin(x)  
\end{gnuplot}, I don't get any gnuplot output.

Thanks for help and regards
Jürgen