Two quick comments:
First, MS Exchange Team: Bravo. I applaud your stance on this as I have been saying almost 100% the same thing for almost 2 years with "VMware experts".
Second, I recommend reading my response on the VMware blog page. To suggest what they posted is simply arrogant and down right juvenile.
Best example I have on the fly:
You bought a Ford Mustang. It comes brand new with a 100K warranty.
Fast forward 2 months. You decided to remove the Ford engine and install an engine from a Ferrari. The car won't start.
You then take the car back to the Ford dealer and say, "Yes my car isn't running, please fix it as I have a warranty" (substitute "support" if you will).
The Ford rep opens the hood and sees that beautiful Stallion logo staring at him. "Sorry, we don't warranty other manufacturer's engines, please contact Ferrari".
See the comedy and arrogance?