Ok so maybe i did not express myself clearly.i found the answer to what i want to do in David Dvorins Logic book.
Incoporating external effects processors."External effects processors can easily be incoporated into Logic by using a special helper plugin that manages the flow from the audio interfaces inputs and outputs to an external processor.With the plug-in connected, you can treat the external processor almost as if it were a plug in itself , inserting it into a channel or applying itas a bus effect in the mixer.
I am not sure if i can do this with the harmoniser i have so maybe someone could enlighten me
thanks
L