can an anchor be a target for an olink?

[natk <nkershaw@gmail.com>]

I am generating an olink db from a docbook file which contains anchors. 

e.g.

<section id="id1">

  <title>Title</title>

  <table border="1">

...

    <tbody>

    <tr>

       <td><anchor id="id2"/>Text</td>

....

The olinkdb file getting generated from this does not produce a title:

<obj element="anchor"

     href="">

     number="" targetptr="id2">

     <ttl>???TITLE???</ttl>

     <xreftext>Section 1.1.3, “Section Title”</xreftext>

</obj>

Are anchors allowed as targets for olinks? If so, what do I need to change?

I am using the maven-docbkx-plugin with version 1.76.1 of the stylesheets.

Nat