Welcome to the forum.
Unfortunately, I do not know the requirements for FaceBook, but there should be an instructions page on their main site.
It might well be that one will have to Export/Share/Publish the finished Video, and then manually upload that to the desired page. However, there might be a setting in the dynamic On-Line Upload settings within PrE. For YouTube, and especially if one has an extended account, that Export/Upload workflow gets around the Duration limitation still coded into PrE. PrE was written before the extended YouTube accounts were allowed. My guess is that PrE 12 will include the capability for handling extended YouTube accounts, but then, they might make a change again, with "super" extended accounts, and one is back to square-on with the manual Export/Upload to allow for the even longer Duration YouTube videos?
Maybe someone, who knows the exact requirements for FaceBook can comment, or perhaps posting to a FaceBook Forum will yield the answers.
If you go to Publish & Share/Computer/AVCHD and you click on the preset dropdown menu, you'll find both a standard definition and high definition preset for outputting video for YouTube.
Thanks to everyone for your reply. I'm new to the forum thing and it's great to have all of you as a resource. Just to clarify, I'm not concerned about uploading to YouTube, that's not a problem. It's just getting the video on to the facebook band page which is a sub page to my personal facebook page. I looked under the AVCHD settings and all of them are larger than the 1280 on the wide side that facebook suggests for best quality, nor is there any choice for H.264 which facebook also recommends. In the Dynamic On-line upload settings for facebook which defaults to 1280 wide and H.264, there appears to be no way to choose which of your facebook pages you would like to upload the video to. Do you think then that it's the case that I'll just have to settle for the upload process to degrade the quality because it will be stepping on a file that's larger than recommended?