All motherboards have a backplate that is designed for the stock cooler or non heatpipe ones that use a clip system.
Looking at the picture from the other thread you have the same water block as me. The back plate that comes with the motherboard isn't the one you use with the water block. You need to take out the motherboard and remove the original one and replace it with the water blocks back plate. While the motherboard is out it is easier to add the waterblock - but this can't be done without draining the system.