Interesting - I was playing around with AirPrint and not having much luck - assumed that it was a Wired/WiFi limitation, but if you have AirPlay (using AirServer) working then might be something else. Much more testing needed.
We experience the same AirPrint issues. Only the first available is broadcasted. THis only happens on IOS devices. Mac OS can see all printers. They are on the same SSID.