Hi. Sorry about the late reply. For any tracks you like to edit, simply click on (Review) and it should bring your track to the wireframe editing view and maybe click on where it says (3D) on the top right of the editor. I assume your at the editing part of the editor. Now there is something that says (banking) on the bottom left. Try this and click on where it says (relative) that should make any bad tweeks go away. Note it won't work unless you click on any section of the track to specify where the problem might be at. Try playing around with the sliders, the buttons and experiment on what you can come up with. Hope that's what ur asking for or maybe someone can explain the details better than I can. For custom inversions you may want to check out the prefab at:
http://www.wounded-heart.com/downloads.asp?product=3