Removing <ackno>

Hello,

I'm creating a DTD that's a subset of Docbook (XML) 4.3. We need to
remove is <ackno>.   I've made w/various attempts, but to no avail.  For
example, I tried the following in the customization layer:

  <!ENTITY % ackno.module "IGNORE">
  <!ENTITY % ackno.element "IGNORE">

However, in XMLSpy, <ackno> is still available for selection after
<para> in the structure <article><para>.  XMLSpy validation does
indicate that the <ackno> element is not declared, but since <ackno> is
available for selection, it seems something else must need to be done.



Thank you -
- george szabo