Series 2 cant find screen to specify brand of cable box in Repeat Guided Setup

I have a Tivo Series 2 (single-tuner) and I can’t seem to figure out how to find the screen where I can specify the brand of cable box I’m using (which is a Comcast DTA aka Digital Transport Adapter, model number DC50Xu). All the Tivo support pages say to go to “Repeat Guided Setup” and select “Cable with box”, but I can’t seem to find a “Cable with box” option anywhere.

Here are the steps I tried… I went to “Repeat Guided Setup”, specified my zip code, then it gave me the following choices on the “TV Programming Source” page:

Cable only
Satellite Only
Satellite & cable
Satellite & antenna
Antenna only

Since I couldn’t find “Cable with box”, I chose “Cable only”, then specified “Internet” (for the IP Address), it then completed the Getting Setup Info step. I then answered Yes to “Cable Box?” and “I don’t know” to “Digital Cable?” (but also tried “Yes” which wasn’t any better). It then put me on the Cable Box Channel Lineup screen. But this is too late, I need the option to specify what brand of DTA I’m using. (I attempted to go thru Channel Lineup anyway just to see what would happen, but it doesn’t control the DTA correctly, it ends up just being a black screen, and I confirmed that my DTA is working fine by hooking it up directly to the TV, and the DTA is configured to Channel 3).

Does anyone know what steps I’m doing wrong while walking through Repeat Guided Setup that is missing the screen where you specify the brand of cable box (ie. “Cable with box”, etc.)?

Also, I thought about trying Settings->Channels->Channel Changing, but the “Channel Changing” option is completely missing. It only has the “Channel List” option. I’m assuming that has something to do with the fact that my Guided Setup didn’t complete, but I thought I’d mention it in case it’s relevant to the issue I’m facing.

Thanks in advance.