As it turns out you need to do some other things when you want to grant yourself this responsibility You have to grant yourself the rights via user management by using the sysadmin account. It looks like a catch 22 however this is in a normal situation something you only need to do when you setup your system the first time and would like to make use of Oracle User Management. In a normal situation (not a test instance) you would provide one user the rights to access this and have this user propagate the rights to other users from within his account.
Looking At Oracle metalink you have to undertake the below steps and indeed, this is the solution for this issue;
1. Log into the applications as SYSADMIN User.
2. Choose User Management responsibility.
3. Navigate to Users web page.
4. Search and find the user you want to inherit the Security Administrator and Customer Administrator Roles.
5. Click on Update Icon.
6. Click on Assign Roles button.
7. Find and choose 'Security Administrator' Role.
9. Repeat the Steps (6-8) for 'Customer Administrator' Role.
10. Log as the user who was assigned User Management Responsibility and facing the issue.
11. Retest the issue.
12. Migrate the solution as appropriate to other environments.