Okay, here's the deal with S3 and the OVAs.
The OVAs ARE Third Term. Specifically, they're eps 25 and 26 of the Third Term series, of which the first 24 episodes have not been animated.
The first 24 episodes can be found in synopsis form on the official website in the "On Air?" section.http://sr.kc.kodansha.co.jp/onair.html
The first 24 eps of Third Term have not, and are not going to be, animated.
The OVAs included scenes from these eps for the specific reason that you're not going to see them animated in any other way.