Server 2003 Automatic Update with Local Administrator

Hi,

I am trying to set up the Automatic Updates facility in Server 2003. I am
logged in as a member of the Local Administrators group, however I cannot run
the update due to restrictions on the ISA proxy server.

I am unable to change the proxy server settings to allow the machine to
access the internet due to security implications.

Is there a way of running the Automatic Update as a different user? I have
tried changing the Service to run as a valid network user (who is also an
administrator) but windows informs me that it cannot be done as other
services in the process are using different log on names. Does anyone know
what these other services are?

Any help would be appreciated,

Cheers,
Martyn...