For those who don't know how......
1. Open a zip program ( i.e Winzip )
2. Open the wooden.pak file found in directory tracks of ultimate ride
3. Drag the first coaster.def file in the list onto the desktop.
4. Now open the coaster.def file using notepad.
5. Change the 0 (zero) in the line "allowinvertpeices" to 1 (one)
6. Save the file and exit notepad.
7. Drag the file back to the list in the zip program.
8. You will now be presented with a dialog. i) Make sure that "add and replace files" is selected
and ii)Make sure that "compression" is set to "none"
9. Once this is done click "add"
10.Close the zip program.
Congratulations, you should now be able to perform Wooden Inversions.