Hi,

I think you have to set a proper notification up. SEP is so reach of events that by default most of them are disabled or sent when a threshold of severity or frequency is reached to avoid a flood of notifications on the admin mail box.
Try the Report and Monitor sections to filter the clients' logs and find the IPS detections.
The SEP Reporting is a big topic, read the product documentation to get more details.

As per my understanding:

For all the mentioned signatures below:

1. Yahoo! IM File Transfer Low
2. Yahoo! IM Login Low
3. Yahoo! IM Activity Low
4. Yahoo! Conference Login Low
5. Yahoo! Ping

Details on the IPS signatures released as we can see it in the links:

http://www.symantec.com/business/security_response...
http://www.symantec.com/business/security_response...
http://www.symantec.com/business/security_response...
http://www.symantec.com/business/security_response...
http://www.symantec.com/business/security_response/attacksignatures/detail.jsp?asid=20571

The Response Part in ALL the documents mention that:

RESPONSE:
While some organizations permit the legitimate use of instant messengers on networks, these programs should be monitored for potential malicious software.

WHICH LOOKS LIKE:
These programs would only be monitored for potential malicious software detection and the normal functionality of YAHOO would not be affected at any point in time

You need to go into Policy->IPS policy->exceptions->find those sigs then change the default behavior from "allow, don't log" -> "Block, log"

rwessen's comment is what worked.  I didn't realize that there were IPS signatures that were not active.   I changed all of the ones set from don't block, don't  log, to allow, log to see what else might be detected.   

this might make for a good forum post down the road, I had no idea these signatures were "on ice."