Castor - Java highly nested XML problem [Spring]

[Kurt Peters]

[this is a cross-post from the castor maillist-got no response there yet]

I got castor to working [unmarshalling] with an "unnested" xml file, but when I nest the elements, it gives me an :error:
of: "Ignoring XXYY no descriptor was found" for anything under the main element "Build".
Here's the "simple" xml:

<MCM>
<Build>1
    <Add>2
        <MNode>1
            <Name>SiteA</Name>
            <Agent id="agent007">
                <Hostname>CentOSHost</Hostname>
            </Agent>
        </MNode>
    </Add>
</Build>
</MCM>

it seems to find everything, but has a problem with "descriptors"... here's the TRACE output:

TRACE - #startElement: MCM
TRACE - #characters:

TRACE - #startElement: Build
TRACE - #characters: 1
   
TRACE - #startElement: Add
TRACE - #characters: 2
       
TRACE - #startElement: MNode
TRACE - #characters: 1
           
TRACE - #startElement: Name
TRACE - #characters: SiteA
TRACE - #endElement: Name
INFO - Ignoring Name no descriptor was found
TRACE - #characters:
           
TRACE - #startElement: Agent
TRACE - #characters:
               
TRACE - #startElement: Hostname
TRACE - #characters: CentOSHost
TRACE - #endElement: Hostname
INFO - Ignoring Hostname no descriptor was found
TRACE - #characters:
           
TRACE - #endElement: Agent
INFO - Ignoring Agent no descriptor was found
TRACE - #characters:
       
TRACE - #endElement: MNode
INFO - Ignoring MNode no descriptor was found
TRACE - #characters:
   
TRACE - #endElement: Add
INFO - Ignoring Add no descriptor was found
TRACE - #characters:

TRACE - #endElement: Build
TRACE - #characters:

TRACE - #endElement: MCM

I've tried an amazing amount of variations on "location," including leaving it out and still, it doesn't map:

<mapping>
    <description>XML mapping of MANDI message will update for collection of nodes.</description>
    <!--  Class Mappings -->
    <class name="org.mitre.mandi.MandiConfigMessage">
        <map-to xml="MCM" />
        <field name="messageType" type="java.lang.String">
            <bind-xml name="Build" node="element" />
        </field>
        <field name="actionToTake" type="java.lang.String">
            <bind-xml name="Add" location="MCM/Build" node="text" />
        </field>
        <field name="nodeToWorkOn" type="org.mitre.mandi.MandiSite">
            <bind-xml name="MNode" location="MCM/Build/Add" node="element" />
        </field>
    </class>
    <class name="org.mitre.mandi.MandiSite">
        <field name="siteName" type="java.lang.String">
            <bind-xml name="Name" node="element" />
        </field>
        <field name="agentID" type="java.lang.String">
            <bind-xml name="id" location="agent" node="attribute" />
        </field>
        <field name="hostName" type="java.lang.String">
            <bind-xml name="Hostname" location="agent" node="element" />
        </field>
    </class>
</mapping>

Any help would be greatly appreciated.
Kurt