This posting is older than 6 months and can contain outdated information.
What I do not understand: Some of the given behaviours have a context menu (when you use them), e.g. EyeTV lets you access the recordings, Itunes you can select from the library.
How do I do that?
You can't achieve this level of integration with Scripted Behaviours. The Behaviours for EyeTV and iTunes are written in Objective-C using Xcode.
The reason asking is: I want to extend (or rebuild) a behaviour for my EyeTV.
Rebuilding will cost you *a lot* of time and you'll loose all special case handling that's part of the EyeTV Behaviour (including special modes for menu navigation) that's difficult or impossible to re-implement in Scripted Behaviours. I therefore can only discourage everyone from doing this. There's nothing to gain here.
I have some extra activities done via applescript and I want to start them from the context menu (as all if my remotes buttons are already mapped).
If all you want to do is add a few actions, the Behaviour Construction Kit is the wrong place to start. For the purpose of extending existing Behaviours, there's the "Custom actions .." item in the action-selection popup at Prefs > Mapping > [Name of the app], where you can add your own actions to an existing Behaviour.
I see that I can drag+drop defined activities to the top level or any folder of the menu hierachy. But I cannot put them into the context menu. (Or, in the case I build by own behaviour there is no context menu at all.)
Verify that you've checked the "Action globally available" checkbox for the respective actions. Your action can then be found in the Menu Item Library under Behaviours > [Name of your Behaviour / Name of the Behaviour you added a custom action to] at Prefs > Menu > [Name of application whose context menu you want to change].
Best regards,
Felix Schwarz