[XeTeX] Using \XeTeXpicfile \XeTeXpdffile command

[Christophe DAMAS]

I try to use the \XeTeXpicfile and \XeTeXpdffile commands in a  
document but I get an error message : unknown command.

I try to typset the PicFileSample.tex file which is given in the  
SampleDoc of the XeTeX distribution, but I get the same message.

This is XeTeX, Version 3.141592-2.2-0.99 (Web2C 7.5.3)
(./PicFileSample.tex
! Undefined control sequence.
<argument> \XeTeXpicfile
                          "xetex.jpg"
\centerline #1->\line {\hss #1
                               \hss }
l.12 \centerline{\XeTeXpicfile "xetex.jpg"}


Can someone help me ?

Christophe