the connections that are created in Admin console are only for Model Repository service(MRS) and not powerCenter.
So, you should be able to see these connections if you login into MRS from the Developer client.
For PowerCenter, you would have to create the connections in workflow manager.
Hope this helps.
Or via the command-line tool "pmrep". There is no other way but WF Manager or pmrep because - as mentioned by Sujata - domain connections cannot be used by PowerCenter and vice versa.