Deleting services from %desktop-services in operating system declaration

[swedebugia]

Hi

I have trouble getting the syntax right to delete avahi and wicd from my 
config.scm.

This did not work (inspecting with the REPL):
  (services (cons* (tor-service) %desktop-services))
  (modify-services (alist-delete
                     wicd-service
                     %desktop-services))
  (modify-services (alist-delete
                     avahi-service
                     %desktop-services))

Neither this:
  (services (cons* (tor-service) %desktop-services))
  (modify-services (alist-delete
                     wicd-service
                     avahi-service
                     %desktop-services))

The manual does not yet have examples of how to delete one or more 
entries from the %base-services or other lists.

Help would be appreciated :)

cheers
swedebugia