Call preservation with SRST

Crunchyhippo

I know that calls using MGCP and CAS will be preserved, but not using MGCP PRI, as the D channel gets torn down and backhauled during SRST, resulting in a dropped call. What about H.323 using CAS and PRI? I've read that Cisco has new features using H.323, but only with a specific (or higher) IOS. But generally speaking, which forms of H.323 will be preserved during SRST?