I have created a visualforce page with standard controller 'Case' to replace with standard new case page. I want it to look exactly like standard new case page but with a controller. The page is called NewCase. So I tried to invoke my page by using this below url: https://ap1.salesforce.com/500/e?retURL=%2FNewCase. But it doesn't seem to work. In the debug log, the operation is /500/e, not my page. Actually, even if I put random data after %2F, it will still direct to the new case creation page - but is the system standard one. Any suggestions on this?
You need to override your "New" page. Setup->Customize->Cases->Buttons Links and Actions->Edit the New Button and select your VisualForce page.
Then when you click New Case, that will take you to your page. If you still want to access the original one, then you can use the URL in your question but you will also need to add