Another supported langauge

Hi 

I'm trying to inject some XML into my FO output but when I do something that
generates this:

<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
<provider>123456789012345678</provider> 
<fo:layout-master-set>

(ie I put in the <provider> stuff that is not part of the FO namespace)

I'm using FOP to generate a PDF I get:

"[ERROR] Unsupported element encountered:  provider (Namespace: default).
Source context.....
[ERROR] Expected XSL-FO (root, page-sequence, etc.), SVG (svg, rect, etc.)
or elements form another supported language."

Now it still generates the PDF but is there a better/proper way of being
able to pass the extra data I need in provider without causing the error. I
now it's not in the FO namespace but I need another process to grab the XML
and do something else with it but FOP still has to be able to produce the
PDF with the same file. 

Thanks
Alan