I've been playing around with TLS, sRTP and ZRTP on a project I'm working on and in the process, I was able to confirm ZRTP works with the Acrobits Groundwire for IOS application. That's great! Now I have a working testbed for ZRTP. By the way, Jitsi works very well in this regard because the setup time for the key exchange is not too significant and it gives the user good visual and audible indication of the connection status.
However, I have not been as successful trying to get TLS to work. In the latest nightly builds for OS X, the sRTP works pretty well and have not experienced any issues there.
In the other applications (i.e., Blink Pro, Bria for IOS, and Groundwire for IOS) and phones (e.g., Yealink, Polycom, Cisco), I selected the TLS transport, sRTP media, and set the proxy and registrar ports to 5061 and they all worked without issue.
I should mention that I generated a certificate for the server and the clients, and all of them including Jitsi imported the client certificate, and use it for authentication, with no issues.
Is there a guide someplace for configuring TLS?