The web service you're calling returns just one string value, which happens to contain XML? So the actual response looks like this? :
<TestClass><inValue1>15</inValue1><inValue2>21</inValue2></TestClass>
I've seen web services like this before, and here are a few options to handle them with Mendix:
System.FileDocument
object, which you can then use in a Mendix XML-to-Domain mapping as you'd normally do.You want to convert the inValue to a Test Class entity. Why not mapping to a TestClass object with a InValue attribute?