Nant - cannot successfully get xmlpoke to work with xml containing namespace information

[chriscomer]

I have successfully setup numerous xmlpoke statements within an Nant
script but this specific situation I cannot figure out. I am including
a section of the xml code I am trying to access and update using an
xmlpoke statement. No matter what I try I continue to get "
[xmlpoke] No matching nodes were found with XPath
expression '/log
gingDistributorConfiguration/xmlSerializerSection/enterpriseLibrary.loggingDistributorSettings'.
Below is the error message, xml file I am trying to modify and the
corresponding xmlpoke expression which fails.

Error Message

[xmlpoke] No matching nodes were found with XPath expression
'/loggingDistributorConfiguration/xmlSerializerSection/enterpriseLibrary.loggingDistributorSettings'.

xmlpoke expression
<xmlpoke
file="..\src\LetterProcessingMonitor\loggingDistri butorConfiguration.config"

xpath="/loggingDistributorConfiguration/xmlSerializerSection/enterpriseLibrary.loggingDistributorSettings"
value="test" />
XML

<?xml version="1.0" encoding="utf-8"?>
<loggingDistributorConfiguration>
<xmlSerializerSection
type="Microsoft.Practices.EnterpriseLibrary.Loggin g.Distributor.Configuration.DistributorSettings,
Microsoft.Practices.EnterpriseLibrary.Logging, Version=1.0.0.0,
Culture=neutral, PublicKeyToken=null">
<enterpriseLibrary.loggingDistributorSettings
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
defaultCategory="General" defaultFormatter="Text Formatter"
xmlns="http://www.microsoft.com/practices/enterpriselibrary/08-31-2004/loggingdistributor">
<sinks>
<sink xsi:type="FlatFileSinkData" name="Flat File Sink"
fileName="LPM_log.txt" header="" footer="" />
</sinks>
<categories>
<category name="General">
<destinations>
<destination name="Event Log Destination" sink="Event Log
Sink" format="Text Formatter" />
</destinations>
</category>
<category name="Category">
<destinations>
<destination name="My First Destination" sink="Flat File
Sink" format="Text Formatter" />
</destinations>
</category>
</categories>
<formatters>
<formatter xsi:type="TextFormatterData" name="Text Formatter">
<template><![CDATA[{timestamp} | {processId} |
{win32ThreadId} | {message} ]]></template>
</formatter>
</formatters>
</enterpriseLibrary.loggingDistributorSettings>
</xmlSerializerSection>
</loggingDistributorConfiguration>