OK, I've made a channel to hopefully accomodate your docking mechanism but can't be sure of the dimensions. Do you work in blender, if so I'll send you the file and you can check them out and let me know or you could make minor adjustments and send it back. All you would need to do is push or pull the faces along an axis until they fit snug. They are nothing fancy, actually might of trimmed off a few pollys getting rid of the recessed area I had there previously.
Edit: Never mind I see that you posted the model in blender format, I can check for myself. Might not get to until Monday though.