[Webtest] file upload in Httpunit

[ramakrishna raju rao]

hi ,
I've written a HttpUnit test case in which I need to 
automatically
upload a file and submit that file.But i am not able to do so.
the following is the code segment where the problem is?

File f =new File("test"); //this is in the same directory
UploadFileSpec ufs[] = new UploadFileSpec[1];
                ufs[k] = new UploadFileSpec(df);
                request = loginForm.getRequest();
                request.setParameter("user-file",ufs);
                request.setParameter("user-choice","File Sent");
                response = wc.getResponse(request);

Iam not getting any response after this step.
Could anyone please help me out with this?