Apple iOS based devices, the iPad and iPod, do not support the use of proxies with apps running on the device. The proxy settings on the device only apply to the built-in Safari browser and the App Store. For example, if you run the Bloomberg app on the iPad, the app tries to connect directly to the Bloomberg server instead of using the proxy settings configured in the iPad settings. Additionally, proxy auto-detect does not work correctly on iOS based devices, so you must manually enter the path to the auto-detect script.
Android based devices like the Samsung Galaxy Tab and Motorola Xoom do not support proxies at all.
SecureSchool, LibraryDoor, ISBossBox
The add-on feature of SecureSchool allows these "proxy unfriendly devices" to connect to the Internet and be filtered, without having to do anything to the device. It does this by transparently watching traffic for the specified IP Groups and routing the traffic through the correct Filter Sets or making the appropriate firewall holes as needed.
All that is required is that these devices must have "predictable" IP addresses. This means they must have either reservations in DHCP or be in a separate IP range / subnet.
In SecureSchool, you would create an IP group for these devices. Assign that IP Group to a filter set that's appropriate for the intended users. Once that's done, SecureSchool Tech Support can then activate the feature for that IP Group.