I have tried this. This does not work. I subsequently returned the B11 heatsink. The heatsink would not fit inside the Air Shroud. Even if you remove the Air Shroud completely, the base black frame separating the memory modules would not allow such installation. In the end I made some modifications and added some fans to the original heatsinks and the temperature is just fine using a dual Platinum Xeon.  

Thanks for your reply.
I found a way out, I found a factory in China that manufactures heatsinks for servers and workstations. They have a radiator in stock that is the size of the original Dell radiator, but only they have a normal radiator with a heat sink of 200 watts.