iTeleport supports external keyboards on the following devices:
Once you're connected to your remote desktop in iTeleport, you need to tap the Keyboard icon to enable the external keyboard.
No Key Limitations
As of the latest version of iTeleport, you can now use your external keyboard without any limitations! This means all keys on your external keyboard, including modifer keys such as Command/Control/Alt/Option, will work and be sent to the remote computer.