Nested annotations in RelaxNG?

Trying to get the following XSD output from RelaxNG, using Trang for conversion:

<xs:annotation>
<xs:documentation>Basic documentation text here.</xs:documentation>
<xs:appinfo>
<jxb:class name="VmlLocation">
<jxb:javadoc>
Javadoc text here.
</jxb:javadoc&g开发者_Python百科t;
</jxb:class>
</xs:appinfo>
</xs:annotation>

.. but none of the methods for declaring annotations seem to work except the RNC '##', which generates one set of annotation/documentation tags. Methods using brackets seem to be ignored by Trang. Any clues?

Trang is somewhat limited, but I know that a:documentation elements that are children of attribute and element elements will be transferred, provided that they contain only plain text (no child elements or attributes). It's possible that a:documentation works in other places too. It definitely does not work as the child of a grammar element or define element.