I have a small hard drive so I have my iTunes library on an external drive. Most of the time I leave that drive attached to my airport and it works great. But, when I travel I like to just bring the drive only so I can have my media. Unfortunately iTunes has to totally rebuild the library every time since the files are in a new location (i.e. same drive, but not as a disk on the network). Does anybody know how I can make that work without rebuilding the library every time?

Thanks!