Thanks for you reply Wanda!
The ADSM Connect Agent makes my work a lot easier for sure, but that's not a 
valid argument for my management, I'm afraid.
The possibility of backing up an Oracle database while in use would be a valid 
reason to buy the Agent if it wasn't possible to do an online backup whithout 
it. However, you can do a  online backup without the Agent. You have to use a 
script to issue the ALTER TABLESPACE BEGIN BACKUP command which allows you to 
backup the database.
You issue the ALTER TABELSPACE END BACKUP afterwards and backup the control 
files afterwards.
Kindest regards,
Eric van Loon