Unattended installation documentation from Novell:

http://www.novell.com/documentation/windows_client/windows_client_admin/?page=/documentation/windows_client/windows_client_admin/data/bty402z.html

How to deal with the non-microsoft-approved SSL cert:

http://www.migee.com/2010/09/24/solution-for-unattendedsilent-installs-and-would-you-like-to-install-this-device-software/

Once extracted you can run certutil.exe (included with windows unlike certmgr.exe) from the command line and preinstall the Novell.cer before running your ACU.exe from the login script. Of course you can adapt the method for ZenWorks as well.