XPath and XML support

I'm doing a performance and scalability test project for a PostgreSQL
user who is working with geospatial data. The data is in GML form.
For instance:

<watch version="9" id="flight" time="2006-08-16T10:16:36.125-07:00">
<point latitude="7" longitude="55"/>
<detail>
<gml:Point xmlns:gml="http://www.opengis.net/gml">
<gml:coordinates>7.0,9.0</gml:coordinates>
</gml:Point>
</detail>
</watch>

I installed PostGIS and it supports Point and coordinates very well.

I an not sure what I should do with the XML content using PostgreSQL?
For example,

1) Tom Dyson at http://www.throwingbeans.org/
postgresql_and_xml_updated.html says "PostgreSQL 8 ships with
xpath_table to evaluate a set of XPath queries and returns the
results as a virtual table."

These look like good XPath functions. Are they actually in PSQL
8.1.4? I did not find them in the Windows installed version. If not,
are they recommended?

2) What is the relationship of the XPath functions to the PostGIS
functions? For example, will I be able to use an index to a PostGIS
field?

3) If the XPath operators are not allowed, should I shred the GML
into two tables (point and detail)?

Any help is much appreciated.

Thanks.

-Frank

---
Frank Cohen, Raining Data, http://www.RainingData.com, phone: 408 236
7604
http://www.xquerynow.com for free XML, XQuery and native XML database
tips,
techniques and solutions.