I use Chromium (or Chrome) as my primary browsers but like keep Camino and Firefox updated with the same bookmarks for occasional use. I am able to successfully import from Chromium and export to both Camino and Firefox, however, my "Bookmark Bar" bookmarks in Chromium were ending up in my "Bookmark Menu" folders in Camino and Firefox (and in Safari too) and not in the Bookmark Bar. I've messed about Client Import/Export settings until I was able to get this to work. For anyone else wanting wanting to do something similar you need the do the following:

1) Under Settings and Client tabs click the import gear icon and set: Default Parent to Chromium (or Chrome).

2) In the Import PostProcessing (Advance) Window, set Default Parent to Bookmarks Menu. Click Done.

3) Now go back and select the Export Gear for Camino/Firefox/Safari/etc.

4)  In the Client: Camino (or other) Advance Settings Window, set Default Parent to Root. Click Done.

That's it. See attached image of these steps.

I hope this help. Perhaps others have been struggling with this as well. I note that the table in section 3.0.2 in the Help document may be misleading. I believe the Bookmarks Bar setting for Chrome should be "Bookmarks menu" and not "Bookmarks Bar", which was the source of my confusion.

Cheers
doug