I haven't used Cover Designer for making covers for audio cds that I have burned in Nero in a very long time, but I occasionally use it for creating covers for CDs/DVDs where I add discs and tracks manually to the cover.
In the Data menu under Document Data... you can add discs and add tracks to discs, and you can type in the name and length of each track.
When you use the Track List tool, you can select which disc and which track numbers to display under Properties... for the Track List object.
I don't know if that's what you wanted to know?!