Spring webflow with subflow not working

i am trying to test my web flow which is having subflow.

i have defined my subflow like below.

protected final Flow buildSubflow() {
FlowDefinitionResourceFactory factory = getResourceFactory();
FlowDefinitionResource resource
= factory.createFileResource("src/main/webapp/WEB-INF/flows/buynet/payment.xml");
MockFlowBuilderContext flowBuilderContext = new MockFlowBuilderContext(resource.getId(), resource.getAttributes());
flowBuilderContext.registerBean("CMCExceptionHandl er", new CMCExceptionHandler());
flowBuilderContext.registerBean("CMCGlobalExceptio nHandler", new CMCGlobalExceptionHandler());
flowBuilderContext.registerBean("paymentService", paymentService);
FlowBuilder builder = createFlowBuilder(resource);
FlowAssembler assembler = new FlowAssembler(builder, flowBuilderContext);
return assembler.assembleFlow();
}


and add below code in configureFlowBuilderContext override method.

final Flow subflow = buildSubflow();

getFlowDefinitionRegistry().registerFlowDefinition (subflow);

when i testing the my actual flow it doen't seems to be going into sub flow.

any idea on what went wrong here.