I'll take a crack at this.

I assume we're talking about the backup archive client and not the server.

To create a service that can be started at boot time to enable centrally 
scheduled ( from an ADSM server somewhere in the network) backups of an NT 
system:

In the baclient directory, there is an executable called  DSMCSVI.exe.  Run 
this and answer the questions.  It will ask you for node name, password etc.  
Once this is completed, use Control Panel Services to look at this service.  
Select it and click on startup.  In this screen you will be able to specify an 
account for this service to log in as.  I use administrator.

This approach creates a process that starts at boot time and does not require 
anyone to log in to the system.

Kelly