IPTC data not read in Extensis Portfolio

Up to and including C1 3.7.3, I could enter IPTC data in Adobe Bridge on my raw P25 files and that data would be recognized in Extensis Portfolio. Upon upgrading to C1 3.7.4 (OS X 10.4.6 on PPC) the IPTC information was no longer written into the raw file, but instead as a sidecar XMP file.

Since Portfolio didn't connect the two files (TIF & XMP), I tried the IPTC editor in C1. Although the IPTC data appears correct in C1, Portfolio is not reading it.

Perhaps this is related to the lost EXIF data in JPEG files? (separate thread) Any suggestions would be appreciated.