I have a similar cable setup and have found that without the CableCard, I was able to tune and get Guide Data for the analog channels only. I could manually select some of the ClearQAM channels but there was no Guide Data for them. I am paying for the HD level service (i.e.: standard channels but in HD) and the CableCard was necessary to get those channels because they are encrypted.
"I'm just one story in a two story town." Bon Jovi