wfs GetFeature request

[N Zhou]

Hi,

I try to query and retrieve specific properties of a feature. My URL request
is:
http://myhost/cgi-bin/mapserv?map=/mymap.map&Service=WFS&version=1.0.0&Request=GetFeature&PROPERTYNAME=water/PID&Typename=water

But I got the full set of properties instead of PID, like the requrest
without PROPERTYNAME. Could any one tell me what is wrong with the request,
or the .map file?

Thank you very much!

N. Zhou

PS: the DescribeFeatureType returned:

<?xml version="1.0" encoding="ISO-8859-1" ?>
<schema targetNamespace="http://www.ttt.org/myns"
xmlns:myns="http://www.ttt.org/myns"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns="http://www.w3.org/2001/XMLSchema"
xmlns:gml="http://www.opengis.net/gml" elementFormDefault="qualified"
version="0.1">
  <import namespace="http://www.opengis.net/gml"
schemaLocation="http://www.opengis.net/gml/2.1/feature.xsd" />
<element name="water" type="myns:water_Type"
substitutionGroup="gml:_Feature" />
   <complexType name="water_Type">
      <complexContent>
         <extension base="gml:AbstractFeatureType">
            <sequence>
                <element name="MS_GEOMETRY" type="gml:PointPropertyType"
nillable="false" />
                <element name="PID" type="string" />
                ......
           </sequence>
         </extension>
      </complexContent>
  </complexType>

</schema>