Status of bug #281: allow xi:include in set

Hello All,

It was reported that xi:include was not allowed in <set>. At
http://sourceforge.net/p/docbook/rfes/281/ it says that the bug is
"fixed for 5.1".

When jing validates my document against the DocBook 5.1CR3 RELAX NG
schema (docbookxi.rng), it reports:
docs.xml:8:34: error: element "xi:include" not allowed here; expected
the element end-tag or element "setindex"

   ,----
   | <?xml version="1.0"?>
   | <set xmlns="http://docbook.org/ns/docbook"
   |      xmlns:xi="http://www.w3.org/2001/XInclude"
   |      xml:lang="en"
   |      version="5.0">
   |   <info>
   |     <title>Set title</title>
   |   </info>
   |   <xi:include href="">   |   <xi:include href="" <!-- line 8 -->
   | </set>
   `----
The document will validate if there is only one xi:include in the <set>
so the sample document above is illegal.

Is there in fact a version of the DocBook schema that will accept the
document above?

Regards,
Test User.