It appears you need to have 2 hacks installed.. one of his smart beds hacks and the ghost hack as well:
"And you can clear bed ownership from a ghost, but if the bed was their 'favorite object', which it almost always is, they will still go and cheer at it because that's stored with the ghost. My ghost hack will fix that."
Found that under
http://www.moreawesomethanyou.com/smf/index.php/topic,5848.0.html~misty