Adding ResponseSLAAssertion using Java and SoapUI API

Hello

I write my own testautomation script in java using SoapUI API.
For adding a XPathAssersion i wrote the method below.

My Question is: How can i add a ResponseSLAAssertion to a teststep
Does anyone have an example or the solustion for me.

Thanks 

CrazyFrog

public static void addXPathAssertion(WsdlTestStep testStep,String assertName, String xpath, String expectedResult)
{
 TestAssertion assertion = ((WsdlTestRequestStep)testStep).addAssertion((new Factory()).getAssertionLabel());
 ((XPathContainsAssertion)assertion).setIgnoreNamespaceDifferences(true);
 ((XPathContainsAssertion)assertion).setIgnoreComments(true);
 ((XPathContainsAssertion)assertion).setAllowWildcards(true);
 ((XPathContainsAssertion)assertion).setName(assertName);
 ((XPathContainsAssertion)assertion).setExpectedContent(expectedResult);
 ((XPathContainsAssertion)assertion).setPath(xpath);
}