Empty response from SOAP Request

Hi. I'm using a webservice of my own where i do some operations, I've tested it with SoapUI and everything works fine. Also, I've created a service in Thingworx which make a request to the webservice I said before, the service executes  properly, but the XML of the response comes empty.

This is the structure of the XML:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:arb="http://arbortext.ipe.ext/">

    <soapenv:Header />

    <soapenv:Body>

        <arb:crearLink>

            <partPadre>OR:wt.part.WTPart:206282</partPadre>

            <partHijo>VR:wt.part.WTPart:198464</partHijo>

            <cantidad>2</cantidad>

            <username>???</username>

            <password>???</password>

        </arb:crearLink>

    </soapenv:Body>

</soapenv:Envelope>

I printed the XML and this is what i get ----> <S:Envelope xmlns:S="http://schemas.xmlsoap.org/soap/envelope/" headers="">Does anyone know what could be the reason of this?

I attach an image of the response using SoapUI

Thank You for your time.