So does this mean you want video analytics? And thermal is not acceptable?
Also, have you choosen Genetec or are you asking about VMS choice?
I don't see this working very well.
Also, you'd really only need closer to a 50mm lens at that distance. 200mm lens would be too narrow of a shot for most applications, especially if you're concerned about false alarms (that what I take from your "less than two alarms..." requirement).
I agree with John, this application is better suited for thermal cameras. In my experience, you're going to have a lot of problems at night (and many times during the day) getting a clear, visible, shot out to 500M with a standard optical camera. However, if the customer is willing to accept that system performance may be comprised during rain/snow/fog or similar bad weather, then it might be OK.
Our product would work with Genetec, Milestone, and most other major VMS's, but I still wouldn't advise using it as you described. This sounds a little bit like "here's my budget, what's the best fit", when this should be approached as "here's my problem, what's the most cost-effective solution".