Instructions are hard to find... From the "wonderfull" RIM docs I get impression that we need to:
Add Service account to RTCUniversalServerAdmins on OCS
Request a TLS/WEB cert from our CA for our all indivudual BES servers that participate in the pool

I event asked RIM and they just sent me the following 3 links:

Provisioning the BlackBerry Collaboration Service as a trusted application - Installation and Configuration Guide - BlackBerry Enterprise Server for IBM Lotus Domino - 5.0.3

KB24960-How to request a TLS certificate to allow the BlackBerry Collaboration Service to communicate with Microsoft Office Communicator Server 2007 R2 or 2010

KB04858-Configuring the BlackBerry Collaboration Service settings

SOo.. has anyone actually done it Do you need to install the OCS web components like you have to On exchange 2010? like documented here?

Integrate OCS 2007 R2 with Exchange Server 2010 SP1 OWA Martin's Wonderful World of Unified Communications

Finally! I found the neccessary KB:

Preparing the computer that hosts the BlackBerry Collaboration Service for use with Microsoft Lync Server 2010

Working on getting the required Cert... once done all should be good I hope

IMPORTANT NOTE: there is a bug with the "Instant messaging server pool is load balanced" Feature. If enabed in a HA pair you will only be able to get one of your two isntances to start. Workaround is to do the following:
Stop Collaboration service on both nodes
Set "Instant messaging server pool is load balanced" (get properties on each colloboration service instance to set). Then restart your services and you should be good... well that worked for me at least

Z