You will need to configure your routers to support IPSLA. Jitter is measured at the router not the Callmanagers. Whip out the IPSLA Admin guide. It will explain how to configure. http://www.solarwinds.com/documentation/IPSLA/docs/IPSLAManagerAdministratorGuide.pdf
have you had a chance to see what we are working on for upcoming IPSLA - http://thwack.solarwinds.com/message/169415#169415? We are currently in beta phase and I think you should definitively try that because you can work with CDR files produced by your call managers and see quality pointers like Jitter, Latency, MOS and much more. I'm going to contact you offline with details.
The same is valid for other IPSLA Manager users - you are more than welcomed to try our IPSLA beta and try all new features.
the jitter, latency and MOS that IPSLA gives you is senthetic from device to device that will accept IPSLA being placed on it.
by senthetic i mean you wont be seeing actual call statistics but data based on the IPSLA route and the test data it sends at programmed intervals.
the call managers will give you the unregistered phones and lots of other stats if you have APM/SAM
some of the other things are:
registered CTI devices
registered media devices
registered voice messaging devices
rejected and unregistered versions of all the above as applicable