To display a content repository in the ACC it must be listed in the initialRepositories property of the /atg/registry/ContentRepositories component.

For example:

initialRepositories+=\
       /betweengo/repository/Portal

From the ATG Repository Guide > 12. SQL Repository Reference > Configuring the SQL Repository Component > Registering a Content Repository:

Content repositories must be added to the list of repositories in the initialRepositories property of the /atg/registry/ContentRepositories component. This also causes the new repository to show up in the Content window of the ATG Control Center.