NullPointerException when using SAML - XML

Hi,

I'm using SOAPUI 4.5.1 and trying to use the SAML XML option when testing my Webservices.
When I paste in a valid SAML2 assertion I'm getting the error below when running the test through the UI and the assertion never gets added to the request. If I use the FORM version everything works fine, but I need the ability to add multiple attributes in the request for testing so I generate my own assertion and use the XML option instead of form.

It appears that the UI is trying to sign the request? My assertion that I pasted in is already signed and works fine.

The funny thing is that if I run the tests through the JUnit/TestNG code.. it works just fine, it's only through the UI I'm getting this error.

Here is the code I'm using for my Unit Tests and this works just fine. The master-soapui-project.xml file is the same one I'm using in the UI as well.

 @Test(groups = {"ReadOnly", "WebServices"})
    public void soapUI() throws Exception {

        // Create the SOAPUiTestRunner
        SoapUITestCaseRunner runner = new SoapUITestCaseRunner();

        // Load the main soap project from the classpath and then get the file location
        URL url = Thread.currentThread().getContextClassLoader().getResource("master-soapui-project.xml");
        runner.setProjectFile(url.getFile());
        runner.setPrintReport(true);
        runner.run();
    }

Wed Aug 15 12:13:59 EDT 2012:ERROR:java.lang.NullPointerException
   java.lang.NullPointerException
    at org.apache.xml.security.signature.Manifest.generateDigestValues(Unknown Source)
    at org.apache.xml.security.signature.XMLSignature.sign(Unknown Source)
    at org.opensaml.xml.signature.Signer.signObject(Signer.java:76)
    at org.apache.ws.security.saml.ext.OpenSAMLUtil.toDom(OpenSAMLUtil.java:129)
    at org.apache.ws.security.saml.ext.AssertionWrapper.toDOM(AssertionWrapper.java:373)
    at org.apache.ws.security.message.WSSecSAMLToken.prependToHeader(WSSecSAMLToken.java:82)
    at org.apache.ws.security.message.WSSecSAMLToken.build(WSSecSAMLToken.java:118)
    at com.eviware.soapui.impl.wsdl.support.wss.entries.ManualSAMLEntry.process(ManualSAMLEntry.java:114)
    at com.eviware.soapui.impl.wsdl.support.wss.OutgoingWss.processOutgoing(OutgoingWss.java:192)
    at com.eviware.soapui.impl.wsdl.submit.filters.WssRequestFilter.filterWsdlRequest(WssRequestFilter.java:58)
    at com.eviware.soapui.impl.wsdl.submit.filters.AbstractRequestFilter.filterAbstractHttpRequest(AbstractRequestFilter.java:37)
    at com.eviware.soapui.impl.wsdl.submit.filters.AbstractRequestFilter.filterRequest(AbstractRequestFilter.java:31)
    at com.eviware.soapui.impl.wsdl.submit.transports.http.HttpClientRequestTransport.sendRequest(HttpClientRequestTransport.java:184)
    at com.eviware.soapui.impl.wsdl.WsdlSubmit.run(WsdlSubmit.java:123)
    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)