I found out too...For those who dont know, RCT3 does a scan of your hard drive for all old rct tracks. Go to the ride menu, and go to the last thing on there (It's an icon with tools on it) and it will scan your HD and after a few minutes it will display your tracks on there. I actually found this out by accident, but now has me started on my SFMW recreation from an imported Zonga I made.