I've got an Logitech Harmony Ultimate remote and I am looking to control my fireplace which is an RF controlled device. There are 6 buttons:
Flame on
Flame off
Heat on 1KW - Press again for heat off
Heat on 2KW - Press again for heat back to 1KW
Light bulb -
Light bulb +

Not sure what the last two do, it seems nothing.

I want to convert this to IR, is there a simple way to do this? The main buttons I would need are the first 4, possibly all 6 though if I work out what the others are for.

I have searched and found various posts, many things which look like they could work but I am not sure. I am UK based, so a UK product would be more helpful however I have found things like this:
[Link: ebay.co.uk]

Would that work? If so - Where do I put that unit? How do I merge the two together to learn my harmony remote the IR command to send?

Or possibly some kind of RF extender with IR compatibility? If so how do I go about that?