Think about it folks, how can you set a SL if there are no episodes that the guide knows about? As far as the guide is concerned, the show never existed. As far as the guide can tell, the show could have been broadcast 20 years or 20 days ago, but it doesn't exist. My TiVo worked the same way. I had to wait for there to be one episode of the show in the guide before I could set a SP on it.
The second flaw mentioned is a LOT more serious. It seems that once you set a SP in TiVO, it's universal for all episodes for that SP whether an episode existed or not. For example, if I set a SP for Heroes, even though there are no existing episodes for Heroes right now, I can go and change the way the series records (when to delete, padding, etc.) On the HR20, it seems that to change any setting, it is based on an episode you choose. Once you go into that existing episode, if there's a SL, then you can change the settings for either that episode or the whole SL, but it HAS to based on SOME episode. Think of it as a computer, where you want to change a whole folder's settings and have it affect everything in the folder. You wouldn't want to go INTO the folder and have to change ONE file in order to change ALL of the folder options. That's silly.
Another flaw with the SL is that if you initially set your SL on a repeat, even though you insist on recording only First Run, it will record that first repeat you based your SL on. AND, I've found, if you go and delete that first repeat, it deletes your WHOLE SL. Try it and see if you get the same results. Since most of the series I have are in repeat mode for the holidays, I was able to find this bug because most of my SL were based on the first episoe being a repeat.