Enterprise Manager

Hi All:
I recently installed GC 10.2.0.4 in linux environment. All our db servers are linux. Acces to the oracle user on these database servers is restricted in that DBAs have to login as themselves and sudo into oracle using their own password
'sudo su - oracle'
there is no way we can login/ssh into these servers as 'oracle'.

as we know most of the functionality, including
*cloning a database/oracle home
*start/sto listener, database
*run a sql script ....and many more require that we provide the Host credentials i.e oracle userid/password. How do I accomplish that? When I provided my own userid which is in 'dba' group , it did not work.

In the setup->preferred credentials page for the hosts there is run as column which can be used to provide my userid and ask it to run as oracle. But this only works when I set at the default level for all hosts ,
when I try to do the same for each host.. it does not allow me to do that .. the 'run as' feild is locked .... any ideas as to how I can fix this ?

also , a lot of places it does not even care for the preferred credentials it again asks for host userid and apssword ... and looks like its willing to take no less than the 'owner' who installed the product ...namely 'Oracle'

please help....