You can program the mx-900 with CCP, but you would have to start from scratch. Can't help with how to get the software.

But if you do have the stand alone mx-900 editor software, you might be able to get the select command from your roku remote even if its Wifi. What is the name & model of roku and its remote model number?

See, recent roku wifi remotes will switch to IR for the roku commands when the roku its paired with is unplugged from the power. Now use it to teach the select to the mx-900, and whatever other roku button you need? This way you don't have to buy a thing.