Need your help again. We have Unity Connection 2.1 installed at our HQ with CCM6.1 and Unity Express with CCME installed at one of our remote sites. We are planning to convert CCME to SRST and register all remote site users to the central cluster of CCM6.1 so that all remote site users can get access to the CCM 6.1 featureset. In addition, we are also planning to put all remote site voice mail users on Unity Connection 2.1 server instead of separate Unity Express module. So here is my question, I have been asked if we could use Unity Connection 2.1 as a Primary voice mail solution for the remote site users and use unity express with SRST as a secondary solution, should the WAN link between HQ and remote site is down.
I have never come across this kinda situation or configuration so if there is any document available explaining the scenario i.e. how to configure unity connection and express in primary/secondary mode, what key points needs to be considered , any additional licences required to make them working in primary/secondary mode, etc would be a great help.