You must specify "[your name].fc2" (be sure to include the .fc2) in the save dialog and navigate to the Runtimelibrariesface[your catagory] folder when you save the file, in order for it to show up in Poser. Simply selecting "Face File (*.fc2)" from the file types drop-down will not change the extension for you.

Beta feedback has been great, so the update should be posted later today... :)

-Rob