Not sure if this helps, but...
Here are some pix on the install on my E36. BMW tends to use the same parts and technology across its entire line of cars (or at least it USED to, which is what I loved about them). So it may be similar on the X5.
On the E36, the radiator has two rubber bump stops on the side brackets and two zip-clips on the top - which tells you how often they expect the radiator to be replaced. They are not intuitive. And they have two rubber bumpers on them as well.
As another noted, the exploded views on RealOEM.com (which are the images from the BMW TIS/ETK discs) show all. The Bentley manual may help, too.
I am going to dig into this, this summer as part of my summer overhaul for Topazblau. I'll try to post pix.
Replace the water pump while you are in there. Cheap part, and it takes 2 seconds to install. And they do fail after 70-100K miles. So you might as well do it..