asterisk 1.8 + SIP/TLS

We are using asterisk 1.8 with Centos. It's an asterisknow install. I have tried for several days to get SIP/TLS to work with a self signed certificate as well as a public cert. No luck. I can get asterisk to say Certificate ok and import the CA via internet explorer but I get several errors. Project is to get this working with documented and replicable steps. I prefer self signed working but would like to see proof of concept for both. Thank you.