But the link does not answer my question.. The article assumes that we can see the Test Cases under the Automated Unit Testing but I do not; although the Test Cases are present when I switch to the PegaUnit testing.
It turned out that the two versions are two different implementations (confirmed after opening an SR). So you will never be able to view the test cases while switching the version.
If you are interested in using the automated run functionality that is not present in the new version: you can use the OOTB Service REST pzExecuteTests found under RS Pega-AutoTest:07-10-25 that triggers the execution of test cases (under new version) from an external system/Continuous integration tools like Jenkins.