How to customize Finder's Share menu?

Solution 1:

I haven't tried it but I would suggestion following :

  1. Copy your automator service in /System/Library/PrivateFrameworks/ShareKit.framework/Versions/A/PlugIns/
  2. rename it Servicename.sharingservice
  3. Now edit /System/Library/PrivateFrameworks/ShareKit.framework/Versions/A/Resources/SHKServicesOrder.plist by adding your service. (CFBundleIdentifier in Info.plist + function name)

Solution 2:

I don't think its possible, at least in a "conventional" way. That contextual menu is populated by adding accounts to the Mail, Contacts & Calendar preference pane, not sure if its even possible to build a workaround for that.