Query Tamino server with xql parameter in URL. Exclude nodes with specific child.

Question

I have to query a Tamino database through HTTP.

http://example.com/db?DocumentType=publication&year=all

gives me a list of all publication in the database, something like:

<publication>
  <title>
    The first publications title
  </title>
  <author>
    Author, M
  </author>
  <LastModification>
    <year>
      2008
    </year>
    <month>
      05
    </month>
  </LastModification>
  <year>
    2006
  </year>
</publication>

<publication>
  <title>
    The second publications title
  </title>
  <author>
    Secauthor, M
  </author>
  <LastModification>
    <year>
      2005
    </year>
    <month>
      01
    </month>
  </LastModification>
  <year>
    2000
  </year>
</publication>

<publication>
  <title>
    Another publications title
  </title>
  <author>
    Anauthor, M
  </author>
  <year>
    2008
  </year>
</publication>

(Simplified values)

There is a xql parameter that can be specified and that can be used to filter the output, so I can do:

http://example.com/db?DocumentType=publication&year=all&xql=LastModification/year~>2008

Which results in:

<publication>
  <title>
    The publications title
  </title>
  <author>
    Author, M
  </author>
  <LastModification>
    <year>
      2008
    </year>
    <month>
      05
    </month>
  </LastModification>
  <year>
    2006
  </year>
</publication>

<publication>
  <title>
    Another publications title
  </title>
  <author>
    Anauthor, M
  </author>
  <year>
    2008
  </year>
</publication>

There is very little documentation... I want to be able to first get all publications that have changed since the last update (and only those), and then in a second query all publications that do not have a <LastModification> tag.