Request for help with olink target data file and @href attribute

I am trying to generate a valid olink target data file for use with HTML 
Help output.
I am using a customization of:

   docbook-xsl/htmlhelp/htmlhelp.xsl

I've run into a problem where the target data file for my document ends up 
with 
the @href attribute values that contain the fragment id, but not the 
document
specifier:

<div element="section" href="#foo" number="" targetptr="foo">
   <ttl>Foo</ttl>
   <xreftext>Foo</xreftext>
</div>

I think the @href attribute shoud look something like:

   <div element="section" href="mydoc.html#foo" number="" targetptr="foo">

How should I proceed?

Taro