Happy Holidays

with all the new Zigbee products due out 1st quarter 2008, I would like to figure out exactly what is needed for 2 way communications, and especially how you would upgrade existing systems

For example: look at this system which I will upgrade to Zigbee:

HT: T4, T2C's, RP-6 (to be upgraded to XP-8)

Whole House: K4's, RK3's, RP-6,T2C's U1's

I know I will have to add some ZM-24 Zigbee Transceiver modules and at least one XP-8

How do I upgrade the remotes? will I have to replace them?

what 2 way capabilities are planned?