I'm not terribly familiar with XSL-FO but it looks like you need a processor to do the layout and rendering. There's no built in support for that in JBoss ESB, but it looks like there's an Apache FOP project that contains a java-based processor. I only took a brief look at it, but it looks like you could probably build a custom action around Apache FOP and have the ESB produce PDF files if you so desire. I'd take a look at the XsltAction for starters.
Thanks for Responding, i didn't found a solution for this, so at the moment it is for me impossible to use xsl-fo in the jboss esb