Just create a new Package Symbol. Don't use the wizard (or use the wizard and then edit the Package Symbol). There is a PDF that goes through the footprint creation process C:\Cadence\SPB_16.5\doc\algrolibdev\algrolibdev.pdf.
You may also look at FootprintGen, EDABuilder, Ultra Librarian for IPC based footprint creation. Many component Manufacturers supply PCB Footprints and Schematic symbols in the Cadence format.
Take a look at the following:- http://www.parallel-systems.co.uk/images/PDF/Footprints.pdf