Problem tagging photos in iPhoto that do now link to Friends on Facebook

Does anyone know how to ensure that tags link properly when loaded to Facebook. I have gone as far as copying the exact spelling from Facebook and create a contact in my Address book. I then tag the photo in iPhoto with that spelling. I then post it to Facebook. They all are tagged properly but some do not link to their respective profiles and they are not notified when I post them. My friends then have to find my posting and tag them again. Or I have to take the time to do it and defeats the whole idea of doing it in iPhoto.