Move from Referenced Library to Managed Library in iPhoto?

Hi,

Because I'm the sort of suspicious type who throws out all the software that comes with any camera I buy I originally set up iPhoto in reference mode (unticking 'Copy items to the iPhoto library')- I hate any program that tries to 'own' my photos.

However since then I have learned a little more and find myself wanting to switch back over to managed mode for all the benefits that entails (many learned people in this forum advise against reference mode).

So... the $64,000 dollar question- is it possible to change my library from Referenced to Managed without losing all of the edits and metadata that I have added in iPhoto over the years?

Do I really just have to start again from scratch with a new library and import it all again?

I did find one thing that could help which was http://www.rorohiko.com/wordpress/downloads/aliasherder/ but comments in the thread I found it in lead me to believe that just replacing the aliases with the files themselves could still leave me in a slightly broken state.

Any and all thoughts gratefully appreciated.