Using XIncludes to include infosets

Hello,

I try to use the new xinclude syntax in my documents but I am not able 
to succed. I have to documents. One of them is data.xml which looks like 
this:

<tip>
     <para id="x25122003">Das sollte man nicht sehen!</para>
     <para id="x26122003">XInclude war erfolgreich!</para>
</tip>

The goal is to include the paragraph with the id x26122003. To reach 
this goal, I inserted the following in my maindocument:

<xi:include href="data.xml" xpointer="id('x26122003')">
...


Since I am not able to succeed with xsltproc, I would like to know if I 
use the right syntax for xpointer or not.

Thanks!

Kind Regrads,

Oliver Fischer