I've got the same issue here, the Microsoft 2.3 program does not recognize the Sculpt Comfort Keyboard.
Instead, it works properly on my desktop.
And as you guys did, I also noticed that the Sculpt Comfort Keyboard isn't listed at this page: http://www.microsoft.com/hardware/en-us/help/windows-8/troubleshooting/mouse/supported-devices
I think that is not the explanation but might be the reason of this problem. I can not understand why Microsoft did not include this keyboard (which I liked a lot) on the Microsoft Mouse and Keyboard Center list, even in it's most recent version (2.3.145)
There is no version 2.3.145 available for download from the official Microsoft hardware support website that I could find anywhere there. The latest version available is 2.2.173.0. You may well have installed hidden malware--and as yet unidentifiable because too new for current detection signatures--on your PC from the file download site where you obtained the unofficial driver. Hopefully not but that is the chance you take when installing unofficial drivers and software from third-party sites.