I managed to figure out the folder:
1. On WIN 7 64B you need to check the show hidden files in the folder table
2. Go to C: Users : Application Data: Izotope. Some times the folder could be in C: Users: Izotope - basically it is located within C: Users
3. I contacted Izotope about this and currently there is no functionality to add new tables. So as Bill points out you need to replace existing ones with new ones bearing the same name. Its a tedious process, can crash the plug in, and the wav needs to be very well defined or it just emits noise.
Those of you who live on the 'edge' go ahead and hack it!