General question concerning encrypted network traffic

Hello.  I searched and was unable to find an exact answer to this question, so I apologize if this has been asked in the past.  I was curious about the issue of the IPS component and encrypted network traffic.  As more web sites (such as Wikipedia this week) are going HTTPS for all traffic, a traditional gateway IDS or IPS will become "blind" to this traffic.  I was curious where the Teefer driver within SEP "sat" in the network stack and if the IPS component of the firewall could "see" encrypted traffic or not.  Thanks for your time.