A Web Form is usually done in two separate pages for clarity: one for the form and one for the acknowlegement, like this:

REUSE ME {code}

Please note that while the form submit to /webform_ack.htm, the application is in /appl/webform_ack.htm.  This is because /webform_ack.htm needs to be from the virtual page in order to have all the fixed features of the template, and the /appl/webform_ack.htm display only comes into the Main Display.