I use automation from Logic Pro into Max quite a lot and then use rewire to get audio from Max into Logic. Works a treat. I just use ctlin for the corresponding MIDI control that I send out of Logic.

MIDI! Doh!

Thanks Dick

it works in max4live and also in pluggo for PT and (older versions of) steinberg hosts.

logic, well, lol.

Yes unfortunately there's the matter of midi resolution limitation but I have used midi to trigger ramps in Max before. It's not ideal but it works.