Old Tutorial
Since Tekken has released I like to show howto add Bam Bam Bigelow. I add him into slot 400. Like usual make backups from everything you change, specially your savegame.
1. Take a look at my old Tutorial and follow step 1 and 2, edit the catalog.dlc and add Bam Bam give him id 400. Rename his .pac file from ch495.pac to ch400.pac, open it with X-Packer and change the pach name from 00049502 to 00040002. Follow ?p=462655 and copy the ch400.pac to your GAMES folder.
2