Proac 2.5 Response tweeter upgrade with Ribbon Tweeter?

I have exactly the same speaker and was looking to do exactly the same thing. 
It would require a lot of cutting amd fiddling about to put a ribbon and won't be cost effective.
The best option would be to buy the d30rs dome tweeter from proac directly. Ill be looking to do this after the new year so ill let you know the reolacement tweeter price