regarding displaying webdynpro based on user

Hi

I have created web dynpro application which is basically a form and portal team has uploaded it on portal. Now requirement is to show the form for some users maintained in ztable and for other give message that they are not allowed.

I tried using WDDOINIT and using sy-uname given the message also but issue is, the form is displayed nonetheless. I donot want to show the form to user if he is not maintained in ztable.

Is there any way to achieve this.

Thanks

Aamir