Has anyone experienced the following problem, and do you know of a better workaround?

I've created a 16x9 24p SD MPEG file using Premiere Pro CS3 frameserving to TMPGENC 4.0. The results are beautiful when viewing the MPEG file. But when I import this file as a timeline into Encore CS3, the Audio and Video are out of sync. The audio sounds correct, and lasts for the entire lenght of the timeline, but the video ends and goes black significantly (minutes) before the end of the timeline. It appears to me that Encore doesn't understand that it's 24p Video and treating it as 30i.

If I set my chapter points referencing the audio track and ignore the video, and build the disc everything looks and sounds fine (in sync) and the chapter points are where I expect them. However, if I let Encore create video thumbnails for my motion menus at the same chapter point, the video in the thumbnail is not showing at the expected point in the timeline - it's much earlier in the timeline (and matches what is shown in the Encore monitor, which is completely out of sync with the audio).

So bottom line is that I have been using the audio (and ignoring video) when setting chapter points, and looking at video (and ignoring audio) when setiting the Poster Frame for motion menus. This is incredibly annoying!

I did some research, and tried renaming ImporterFastMPEG.prm so that Encore wouldn't find it. This did correct the sync issues on the timeline, BUT rendering my 6 menus with 4 thumbnails on each is taking about 9 HOURS! Yuck!!!

Does anyone have any advise for me on this?