See answers below, please let me know if you have any other questions.
I guess the first question is to what client/endpoints do you want to display presence? Jabber (video) / Movi / desktop endpoints & voice (phone)
Do you have IM currently or are you just now looking into the IM client? We are currently using Microsoft Link for IM
What products are you looking to provide or set presence? (Outlook, phone status, IM Client, etc) ) Jabber client, Jabber (video) Phone status (voip), jabber client.
So where can you start? The sooner the better! starting with drawing an architecture design that can support Presence, IM, Voice and Video (Jabber) for a total of 10,000 users. Determine what major components will be needed in addition to what we already have in production.
that will explain a bit more of the integration of CUP with the Microsoft Component.
Without going into specifics about your deployment, you will need to understand how products relay presence and how each component in your deployment publishes and receives presence information. Please review the documents I have included for additional details on their integration. I am not sure I can help much beyond this without going into your specific deployment requirements.