LF: Automator Script for iTunes

[alfiesy]

I have a music collection both in mp3 (160kbps) and AAC (128kbps) file format. Am looking for an automator script that would:
1.) convert all my mp3's into AAC's in my library
2.) delete converted mp3's from my library
3.) put back the resultant AAC's in playlists on my library wherever the source mp3's were found.

Thank you for any leads on this.