Hi,

>I run an xsl stylesheet to make a pdf which contains the expression:
><fo:external-graphic src='{$logo}' ...
>
>I use this expression because I want to insert an icon.
>
>It works fine when $logo=file:c:/icons/logo.jpg, but I would

See XSL spec, src attribute value space is a uri-specification, so you want

  <fo:external-graphic src='url("{$logo}")' ...

>like to read this image from a jar file and in this case I
>have not found the good syntax.
>I have tried $logo=file:archive.jar/icons/logog.jpg but still
>unsuccessful.
>
>Is it possible to do it by this way ?

Check the documentation of your XSL engine and if they support reading files
from JAR files.

Jarno