id attribute in term elements

Hello,

In my docbook document, I was referring to ids in term elements of
a variablelist. For example:

  <varlistentry>
   <term id="partype.Text">Text</term>
   ...
  </varlistentry>

   ...
  <link linkend="partype.Text">Text</link>
   ...


While this works perfectly well with the HTML output, it doesn't 
resolve when I try to generate the PDF output with XEP.
I get the message:

  [warning] unresolved internal destination: 'partype.Text'

If I move the id attribute from the term element to the varlistentry
element, that is

  <varlistentry id="partype.Text">
   <term>Text</term>
   ...
  </varlistentry>

no more warning is generated.

Is it incorrect to use the id attribute in term elements?

I am using XEP 4.0, xml-dtd-4.4CR2 and docbook-xsl-1.67.2


Diane Larin
INRO