For some reason the latest version ( 2.0.9 ) of the plugin produces :

Embedded error: org.apache.fop.apps.FOPException: null:1:28951: Error(1/28951):
No element mapping definition found for (Namespace URI:"http://xml.apache.org/fop/extensions", Local Name: "destination")

I had to rely on version 2.0.8 this sole behavior stole hours from me.

I also could not add an image in the fopdf.xsl on the cover page.

<fo:block>
	<fo:external-graphic src="file:images/logo.png"/>                                       
</fo:block>

Not working

I had to use this notation instead:

<fo:block>
	<fo:external-graphic src="file:src/docbkx/resources/images/logo.png"/>                  
</fo:block>

Working

Even if this kind of bug seems obvious, it was not that easy to find when mixed between version problems, dependency hell, syntaxic errors etc.

Anyway, hopefully this will help you to build great looking documentation.