[whpalmer4]

It's not really supported in OmniPlan 1.7. However, OmniPlan 2.0 allows specifying on a per-action basis whether you want As Soon As Possible or As Late As Possible scheduling. I made good use of this on my project plan for my Thanksgiving dinner :-) Prep work on various dishes got ASAP scheduling, and the actual assembly and serving of the dishes got ALAP scheduling against a milestone set at dinner time. The OmniPlan developers have been hard at work, and a lot of wish list items are going to be checked off when it ships.

If you really need to do this now, you set things up with Finish->Start dependencies, and manually work your way backwards from the finish, dragging things into position as late as possible (just before the violation warning shows up). The leveling function won't be of much use with all the tasks locked in position like that, so you'll need to be able to figure it out yourself, but you certainly can use it to calculate backwards from a finish date along a path of your choosing.