SOAPUI - xpath engine/parser seems that arthmetic operations do not works there

I have following problem.

I am sending SOAP request and after getting response I need to "Get Data" from it, add "1" and send back as another SOAP request.

My SOAP response to analyze is like that:

<multiRef id="id0" soapenc:root="0" >
         <name xsi:type="soapenc:string">basketId</name>
         <value xsi:type="soapenc:string">12</value>
      </multiRef>

I want to get that 12 and add 1 to it: I do it in SOAP UI by XPATH inserted in new request (I do not want to use anything else). Pure XML of new request looks like that:

<multiRef id="id1" soapenc:root="0" >
    <name xsi:type="soapenc:string">basketId</name>
    <value xsi:type="soapenc:string">${GetBasketID_3#Response#//multiRef[name="newBasketId"]开发者_如何学编程/value/text() +1 }</value>
</multiRef>

the xpath expression is:

//multiRef[name="newBasketId"]/value/text() + 1 

With xpathchecker in Firefox this works, but SOAP UI sends empty value there. How can I make push SOAP UI xpath parser to work or write xpath expression in working way?

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If you provide the entire XML, it will be easier to provide the exact answer. However you can try the below xpath. The problem can be related with the missing namespace .

${Test Request#Response#declare namespace ns1='http://ADDNAMESPACEHERE'; //multiRef[1]/value[1]/text()}