Yes, I'm referring to the Allegro PCB Librarian XL "product license". If you aren't running that you will not see the symbol on the canvas... But like you said you can edit the symbol in Allegro HDL. Within PDV you can click on the symbol and then click on Tools --> Design Entry HDL. It will open Allegro HDL.
PDV is very buggy so I find it much easier to do as much as possible outside of PDV and then go back in to PDV to do a save.