I am running the bloody build, and the IR worked straight off the bat
I had an issue though, as I also run my Windows Media Center PC in the same room with an IR reciever, and using the Harmony or the WMC remote was controlling both the PC and the Slice at the same time.
I found this blog useful to allow me to change the ID of the WMC remote, so I can configure my WMC PC and Slice as a WMC Extender, allowing me to control either device independently.
I still need to get the harmony to learn the codes from the WMC remote so I can control the PC, but thats no problem.
Set Remote Control ID
Hope it may help anyone else who may be having this issue
EDIT I am using the Harmony Ultimate One