Eric, Looks like a rebadged Polycom to me. If you have no luck, send me a Pm and I'll see what I can find out from our support connections.
Most POE is 48 volts, most commonly supplied over the White blue and white brown pairs of the Cat5. (4&5 is positive 7&8 is negative) That said 24 volts is also used for some devices.
If you have the correct POE injector that's a start but you need to be able to determine the polarity, like most standards POE unfortunately isn't standard and the polarity of the plugpacks is variable. Most but not all POE adapters will have a blocking diode to prevent accidental reverse polarity connection. If you can dismantle the adapter that may give you some idea of any polarity requirements.
Some info here
http://pinouts.ru/Net/poe_pinout.shtml.
I wouldn't worry too much about the extension mics, they make bugger all difference unless you have a very large conference room.