[XeTeX] fontspec - color and transparence

[M. Niedermair]

Hi,

i try the following example (see 5.3 from the fontspec-document), but i 
get no transparent colors.

Any tip?

By
Michael

\documentclass{minimal}
\pagestyle{empty}
\usepackage{fontspec}
\begin{document}
\newfontfamily\Libertine{Linux Libertine O}
\Libertine
\fontsize{48}{48}
{\addfontfeature{Color=FF000099}W}\kern-3ex
{\addfontfeature{Color=0000FF99}S}\kern-1.8ex
{\addfontfeature{Color=DDBB2299}P}\kern-1.8ex
{\addfontfeature{Color=00BB3399}R}
\end{document}