Currently trying to gather maximum info about this hardware and write my own plugin for it. (Although i'm newbie in programming :?)
P.S. Recently experimented with "girder-HID plugin" combination: half-a-work.
If someone needs some info about subj hardware, feel free to contact me.
It's freeware and operate similar to Girder but has a *lot* more power as far as I can see. If the Logitech works as a HID USB device then HIP (the program linked to above) can intercept the commands and let you remap them.
HIP also was the variant, but in refuses to work (thru HID interface) with UltraX
P.S. As I see and understand, Logitech UltraX Media Remote Receiver identifies by OS as a composite USB device: HID keyboard and 2 HID compartible devices which generates raw codes with similar values (that's why people talk about identical codes from different buttons on remote), but software that comes with remote (MediaLife 2005) distinguishes keycodes by device system subcodes (Vid046d&Pid_c101&Rev_0103&MI_01&Col01 and Vid046d&Pid_c101&Rev_0103&MI_01&Col02)
However, note that this is more of a "proof of concept" than a plugin. It is at the moment not configurable, but it does let you use most of the buttons on the control. My hope is that someone can use this source to create a plugin that can be integrated with the other controls that MediaPortal supports.
Please download it and give it a try. I've successfully installed and used in two computers.