CrossRoads, 0.99 mA seems a bit too much for the power-down mode. Are you powering your RF interface down too?
My board, RF circuitry included (CC1101), consumes less than 6 uA in Power-Down state. Watchdog enabled. If I wanted to wake up the atmega from an external INTX pin instead of the watchdog, I should be able to reduce the consumption down to 0.2 uA.