I found a few threads which deal with a way to add commands which your device understands, but are not available on the original remote (e.g. seperate power ON OFF commands instead of a TOGGLE).
There seems to be a way to add one PRONTO code, but it's limited to just one command and I do not know if it still works.
As I am actually having the same issue, I had another idea to solve it: I would need a PC SW or an App on Android (e.g. RCoid) and a supported IR transmitter (my mobile has none) which allows to enter IR codes (RC5/pronto/..) into the SW and send them though the IR transmitter. After testing it with your device you can then learn it into your harmony as you would with the original control. That way you could add multiple commands.
I have googled a lot, but for Android I only found the App above but I seems to support only phones with built in IR. IR transceiver with headphone jacks seem to be off market and USB versions support just one App which has no code entry. For PC I found a few (expensive) USB IR transceiver, but no SW to my needs.
