1. UID is already in the REQUEST/REPLY iTIP methods for VFREEBUSY. It is not in the PUBLISH method, as there is no need for it. There is no scheduling workflow in iTIP for the PUBLISH method on VFREEBUSY.
2. COUNTER is an unnecessary method for VFREEBUSY in the the current iTIP. The busy time request scheduling workflow is a single pair of REQUEST/REPLY. The idea of using a COUNTER method to request another set busy time information is not appropriate, as a CUA would instead make another separate REQUEST method.
This issue should be closed or marked as moot.
-- Frank