Disable Cisco Anyconnect automatic startup at boot.

Not so easy.. some references:
https://supportforums.cisco.com/discussion/11643501/anyconnect-3101-disable-client-startup
https://tools.cisco.com/bugsearch/bug/CSCtn12023

Best solution so far seems to be renaming the vpnui.exe on client machine.
To avoid scripts I decided to rename the file in the anyconnect MSI installer package.
Under the File table, find a vpnui.exe entry in FileName and rename it to vpn.exe
That way the anyconnect GUI client is installed as vpn.exe preventing the startup from launching vpnui.exe.
Also added screenshot: