Good news, your mce remote/receiver will work on install. The USB-UIRT is used to control IR devices.
For example, my core, has a dish network receiver, a sirius satellite receiver, a RCA AV Dolby Digital receiver, and a 42" Big screen TV. Using the USB-UIRT to learn each one of those devices remote control (this is very simple to do through the web admin after install) once all of the codes are learned, no matter which device I use, it has all been consolidated to a single mce remote, so if I want to watch a dvd, it automatically changes the input on my AV receiver to DVD, puts the TV on the correct input, and does it all with a single button press on the mce remote.
I also use it to change the channels on my dish network receiver, and all I had to do was learn the receivers codes. LMCE knows exactly what device to control, and which inputs to use, all controlled by IR and the USB-UIRT.
This is the main feature for me of the USB-UIRT, the ability to learn and reproduce any IR code I throw at it.
After the receiver is installed, it is automatically set up, and allows you to use your existing mce remote. This gives you the option to put your other receiver on a future media director (MD) and just carry the remote back and forth, so you have 2 places controlled by the same remote, and if you are on an MD, and you want to change a channel on the STB for cable or dish the MD sends the commands to the core, and blasts them using the USB-UIRT, so you can be in another room, and still have access to your main core devices.
Definitely a worth while purchase.