How to get test instance details from Test Set in HP QC-OTA Client Java / C#

Question

Actually, I need to retrieve all test instances which is been loaded up in Execution Grid tab from the given TestSet ID using C# or java

Here is my code (JAVA):

        ITDConnection tdc = ClassFactory.createTDConnection();
        tdc.initConnectionEx(url);
        tdc.connectProjectEx(domain, project, username, password);

        ITestSetFactory sTestSetFactory = (tdc.testSetFactory()).queryInterface(ITestSetFactory.class);   
        ITestSet sTestSet = (sTestSetFactory.item(1301)).queryInterface(ITestSet.class);   
        System.out.println(sTestSet.name());

Using above piece of code I was able to retrieve the name of the TestSet

        ITestFactory iTestFactory = sTestSet.tsTestFactory().queryInterface(ITestFactory.class);
        Com4jObject oTest = iTestFactory.newList("");
        ITest iTest = oTest.queryInterface(ITest.class);
        System.out.println(iTest.name());

but when I'm trying to connect TestSet obj to testfactoy I'm unable to achieve it. Am I missing anything? Can anyone help me please?

Thanks