MockServer - XPATH not working

I have mocked server created with MockServer. It have to answer for requests with parameter with specified value. I have simple SOAP message sent as text/xml:

<soapenv:Envelope xmlns:soapenv="http://ift.tt/sVJIaE">
   <soapenv:Header/>
   <soapenv:Body>
      <x>y</x>
   </soapenv:Body>
</soapenv:Envelope>

On mocked server side I want to check if parameter x is equal to y. So I am testing it with online xpath parser http://ift.tt/1i4Ssa3 and it works. My XPATH expression is:

/soapenv:Envelope/soapenv:Body/x='y'

So I want to set rule on MockServer based on this XPATH and it doesn't work. Log says that body doesn't match.

My MockServer code:

        MockServerClient mock = new MockServerClient("localhost", 12121);
        mock.reset();

        mock.when(
                request()
                        .withBody(StringBody.xpath("/soapenv:Envelope/soapenv:Body/x='y'").getValue())                          
        )
        .respond(
                response()
                        .withStatusCode(200)
        );

Request is logged to file on mockerver side and all those backslahes and new line symbols are printed and I am wondering if it's not something wrong with that, but probably it is not the case and it's only added when logging to file:

<soapenv:Envelope xmlns:soapenv=\"http://ift.tt/sVJIaE\">\n
    <soapenv:Header>
          <wsse:Security xmlns:wsse=\"http://ift.tt/LRW8Ij\" xmlns:wsu=\"http://ift.tt/Hm2joJ\">
              <wsse:UsernameToken wsu:Id=\"UsernameToken-12\">
                  <wsse:Username>a</wsse:Username>
                  <wsse:Password Type=\"http://ift.tt/1aTA7XU\">a</wsse:Password>
                  <wsse:Nonce EncodingType=\"http://ift.tt/14yUvuM\">n0ktTNd2fplBouQcI7cc/Q==</wsse:Nonce>
                  <wsu:Created>2015-02-17T08:38:55.834Z</wsu:Created>
              </wsse:UsernameToken>
          </wsse:Security>
    </soapenv:Header>\n   
    <soapenv:Body>\n      
        <parameters>sda</parameters>\n
    </soapenv:Body>\n
</soapenv:Envelope>