Xpath results in empty variable

I am very confused about the property mediator in the WSO2 Micro intergator suite. There is a field that I need to extract using Xpath and then send to AWS SQS. The following is the document from which I try to extract the field (note that I cropped the bottom half of the document).

<?xml version="1.0" encoding="UTF-8"?>
<s:Envelope
    xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Body>
        <Waybill
            xmlns="urn:oasis:names:specification:ubl:schema:xsd:Waybill-2"
            xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"
            xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2"
            xmlns:eba="http://ns.tln.nl/eba/schemas/1-0/"
            xmlns:ext="urn:oasis:names:specification:ubl:schema:xsd:CommonExtensionComponents-2"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="urn:oasis:names:specification:ubl:schema:xsd:Waybill-2 http://docs.oasis-open.org/ubl/prd1-UBL-2.1/xsd/maindoc/UBL-Waybill-2.1.xsd http://ns.tln.nl/eba/schemas/1-0-1/EBA-Extensions.xsd">
            <ext:UBLExtensions>
                <ext:UBLExtension>
                    <ext:ExtensionContent>
                        <eba:ReplyAddress>
                            <eba:Webservice>
                                <eba:WebserviceEndPoint>http://www.google.com
                                </eba:WebserviceEndPoint>
                                <eba:Username>123</eba:Username>
                                <eba:Password>123
                                </eba:Password>
                            </eba:Webservice>
                        </eba:ReplyAddress>
                    </ext:ExtensionContent>
                </ext:UBLExtension>
                <ext:UBLExtension>
                    <ext:ExtensionContent>
                        <eba:ReplyAddress>
                            <eba:EmailAddress>[email protected]</eba:EmailAddress>
                        </eba:ReplyAddress>
                    </ext:ExtensionContent>
                </ext:UBLExtension>
            </ext:UBLExtensions>

I'm looking to parse the "Waybill" part. No matter what I try with the property, the result is either going to be an error (syntactical) or an empty result.

Examples of non-working code I tried thus far:

<property expression="//s:Body/Waybill" name="wayb" scope="default" type="STRING" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" />

<property expression="$:Body/Waybill" name="messageBody" scope="default" type="STRING" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns="urn:oasis:names:specification:ubl:schema:xsd:Waybill-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:eba="http://ns.tln.nl/eba/schemas/1-0/" xmlns:ext="urn:oasis:names:specification:ubl:schema:xsd:CommonExtensionComponents-2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:oasis:names:specification:ubl:schema:xsd:Waybill-2 http://docs.oasis-open.org/ubl/prd1-UBL-2.1/xsd/maindoc/UBL-Waybill-2.1.xsd http://ns.tln.nl/eba/schemas/1-0-1/EBA-Extensions.xsd"/>

<property expression="//Waybill" name="messageBody" scope="default" type="STRING" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns="urn:oasis:names:specification:ubl:schema:xsd:Waybill-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:eba="http://ns.tln.nl/eba/schemas/1-0/" xmlns:ext="urn:oasis:names:specification:ubl:schema:xsd:CommonExtensionComponents-2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:oasis:names:specification:ubl:schema:xsd:Waybill-2 http://docs.oasis-open.org/ubl/prd1-UBL-2.1/xsd/maindoc/UBL-Waybill-2.1.xsd http://ns.tln.nl/eba/schemas/1-0-1/EBA-Extensions.xsd"/>

<property expression="//Waybill" name="messageBody" scope="default" type="STRING" />

Note however that I can easily grab the body field which DOES work:

<property expression="$body" name="messageBody" scope="default" type="STRING"/>

What am I missing here?

Solution

The issue here (as is the case with many xml snippets) is the use of namespaces; as the experts will tell you, they are necessary - but, in my opinion, a necessary evil....

One way to deal with them is to disregard them when possible; that, in turn, can be done by using xpath's local-name() function.

Or, in this case:

//*[local-name()='Waybill']