Looking at the datasheet for this piece I see that support for CME "will be supported in the future". Is the future now? Will this work on a UC520 system running V4.2? Also, does the mic kit bring one mic or two? The picture shows two mics but the description of the actual kit is not clear.
Just to add a note to the great tips from Nick (+5 points here Nick :)
The Mic Kit does come with 2 external Mic's. I have one sitting in front of me right now (pretty cool looking little guys!).