MockResponse get stuck in Load Test

Hi everybody,

I need to test application which send many SOAP requests and than receive SOAP requests. My workflow:

Test step 1 - MockResponse to accept the asynchronous requests - SoapUI receive request with sessionId and send response;
Test step 2 - Send Request (do some processing) with sessionId the same as on Test Step 1 request, after several seconds (processing done) receive Response from my App;
Test step 3 - Send Request (release) with sessionId the same as on Test Step 1 request and receive Response from my App.

It work fine in single iteration, but when I run Load Test and send fo example 5 requests to SoapUI, first 1 or 2 iterations work Ok, but 3 and etc. get stuck on Test Step 2 - I see ( in my App trace) response from SoapUI on Test step 1, but Test step 2 request is absent .

I tried Mock Service groovy script what run my Test Case (I disabled Test step 1):

def groovyUtils = new com.eviware.soapui.support.GroovyUtils(context)
def holder = groovyUtils.getXmlHolder(mockRequest.requestContent)
holder.declareNamespace( 'cms', 'http://www.bercut.com/specs/ao/sal/cms')
def testCase = context.mockService.project.getTestSuiteByName("TestSuite").getTestCaseByName("Incoming Call TestCase")
testCase.setPropertyValue("sessionId", holder.getNodeValue("//cms:onIncomingCallRequestParams[1]/sessionId[1]"))
def properties = new com.eviware.soapui.support.types.StringToObjectMap ()
def async = true
testCase.run (properties, async)

It work, but when my App sends more than one Requests, sessionId Test Case property is overwrited each time and on Test Step 3 (release) stage it's already wrong? I expect that each Test Case is run in separate thread and sessionId is stored for each Test Case separate? but this is not the case.

Thanks for any help

P.S. My company purchased License for ten users. Version SoapUI is 3.5.1 (Build dist-97-2010-04-12, Build Date 2010/04/12 09:51)

Sorry for my language.