Well, if you look closely at the CCF, there are several pages labelled Functions 0-59, 60-119, etc... These pages contain all the function codes (all 256) for the Mits TV Device.

You will need to test all 256 (minus known functions) of these function buttons to determine which one puts you on the HDMI input. However, as a hint, you can look @ known buttons, for example Keypad 0, and you will see, upon opening properties, that the label for the IR Code is the actual function ID. You can exclude the functions that are known from your test.