Tell your IT guys that Mac is a variant of Linux (which is basically true) so networking is easy and reliability is greater than Win boxes. Tell them the hardware is already state of the art and doesn’t need constant upgrade except perhaps RAM and graphics cards. Tell them you don’t need anti virus software that needs constant updating.
You can also tell them that in my facility we have four Win XP machines, two Macs and two Linux boxes. We have no IT people because you don’t need them if you take the time to learn the basics about the tools you work with. The Win machines require a lot more maintenance and were the most difficult to setup.
Finally you can tell them that their job is to learn to maintain the tools that are required to get the real work done. They are support, not the creators of the actual product that you produce so they have to learn to manage the tools, not determine them. There is no reason why any IT pro with basic intelligence would worry about integrating a Mac into a system that already has Win and Linux boxes.
If they haven’t the skills to do the job, then replace them. IT facists are a dime a dozen. Chose real IT support people as carefully as you choose your edit systems.