[Users] (open)SER and ICE

Hi, As I'm a newbie on this subject, I'm wondering how two SIP devices with ICE compatibility will interact with a (open)SER+Mediaproxy implementation since ICE implementation could permit to avoid RTP flow on the (open)SER server. Is there any update to do on the conf file on the (open)SER ? Since they are ICE compatible, the SIP flow (signalization) will be analysed by this two devices in order to create a direct RTP flow ? Or is it because i know on the (open)SER side that this devices are ICE compatible I send a special SIP message ? In fact I want to know if a server update is necessary or if it's "free" to have this great feature. :) Thanks, Christophe