Where did you get the name "EPAS"?
EPAS is an internal code name for Cisco Unified Presence Server. I think it stands for "Enterprise Presence Application System".
There are couple different logs under the EPAS umbrella. Some of the most important logs are PE (Presence Engine), Proxy (SIP Proxy) and SA (Sync Agent).
You may get those logs with RTMT (Real Time Monitoring Tool) or CLI (Command Line Interface).
On CLI, you may list the logs with command "file list" and get the logs with command "file get".
For example:
file list epas/trace/epe/sdi (Presence Engine logs)
file list epas/trace/esp/sdi (SIP Proxy logs)
file list epas/trace/epassa/log4j (Sync Agent logs)
file get epas/trace/epe/sdi/epe00000001.txt
Hope this helps!
Michael
http://htluo.blogspot.com