iDVD, for why do you not use my chapters!?

Video editing on my new PowerMac is very nice. Compared to my old 800MHz iMac, this new dual-1.42GHz PowerMac is a speed demon. Lately, I've been grabbing some shows off the TiVo and archiving them. The convoluted conversion process I have to follow goes something like this:

1. Download show off of the TiVo using MFSStream
2. Convert .ty source file with TyConvert X.
3. Demux resulting MPEG-2 file with bbDEMUX
4. Encode resulting .m2v file into format of my choice (DV for iDVD projects, in particular) with DiVA
5. Convert .m1a audio to AIFF using madplaywrap and MAD.
6. Normalize resulting audio file with Sound Studio
7. (optional) Compress AIFF file into MPEG-4 AAC or something smaller (if I'm not outputting to DVD).
8. Use sync-hole to combine and sync audio/video tracks between the DV file (or whatever output compressed format I chose) and the audio track.
9. Use Quicktime Pro to edit out commercials
10. (optional) Save as a self-contained movie

If I'm going to DVD, I end up with a large DV file that I bring into iDVD. The iDVD product page says that iDVD will read chapter tracks within a Quicktime file and then use them within a project. Does this work? Yes, for iMovie, no for the chapter tracks I've been added to my movies. Once I create the chapter track and add it to my DV file, Quicktime works fine with it. But, bringing the file into iDVD does nothing. iDVD doesn't even recognize that there's a chapter track there.

And, I can't take my huge DV file and import it into iMovie because iMovie has a limit to the size of clips you can import. Argh!

I wonder what I'm doing wrong here. Am I asking too much of iDVD, or is there a bug that prevents it from reading chapter tracks from files created with Quicktime Pro?