ZENworks understands icons in png and ico format. OS X uses icns format for its icons. I have created a clickable script using native OS X tools and a compiled copy of the open source png2ico tool ( borrowed from http://harvey.nu/installers ) that will bluntly create png and ico versions of every icon associated with the OS X application that you select. These files can then be uploaded to ZENworks Configuration Management and associated with OS X bundles, where they will then show up in the ZENworks Window.
The file included here is a package installer that will install the necessary files to /Applications/ZENWorks Cool Tools/zenicon/ . The readme.txt in that folder has further details on usage.
Please let me know if you find this tool useful, and how it might be improved.