Hi,
Pm me with a sample if you can, I'll have a look over the week end. I am sure it's possible to insert a script that will bridge the collision detection with your fsm, it could mean building a custom action as well, but I am pretty sure you don't need to redo everything. I do that all the time on a project where I have a greta mix of existing scripts and fsm that are bridges together in various ways.
Bye,
Jean