Updating busy information greyed out
Eventually the Calendar share settings on the user accounts will allow you to change the default "See only free/busy (hide details)" choice to "See all event details" and you're done.
Here's an updated link that sets the Calendar sharing option.
Overcoming the problem This problem should be distinguished from the viewing of hidden folders in the Finder.
OS X contains a number of hidden folders to keep your system looking clean, but there are hidden settings that can be activated to show these folders.
Empathy fades to gray, and after 1 or 2 seconds it goes back to normal, and I could enter the jabber account information.