Property source is not a request

Hi Team,

I am having an issue with the property transfer in the rest API.

I am not able to declare namespace in Request and Response.

When ever I am Clicking on ns: - it is displaying an error as 'Property source is not a request'.

In the Request - I have configured the media type to text/xml

Below is the request : 

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
	<soap:Body>
		<GetRateOptionAvailability>
			<AMAKey>${#TestSuite#AMAKey}</AMAKey>
			<CruiseCode>${#Project#CruiseCode}</CruiseCode>
			<CurrencyCode>${#TestCases#CurrencyCode}</CurrencyCode>
			<IATANumber>${#TestSuite#IATANumber}</IATANumber>
			<SailID>${#Project#SailID}</SailID>
			<PassengerCityCode>${#TestCase#PassengerCityCode}</PassengerCityCode>
		</GetRateOptionAvailability>
	</soap:Body>
</soap:Envelope>

Please refer screenshot for more information.