Please use Reaktor 4 FX as an insert effect.Then you don´t need a sidechain. In the Logic track automation 64 midi controllers are available which can be assigned to Reaktor controls. Assign midi controller numbers to the controls on the effect, activate remote and panel to midi out.Deactivate internal midi routing (all that in the properties of instrument and control). In Reaktor 4 the names of the controls will be visible in track automation.