Hi Stefan,
Yes, you have to import newer adapter metadata (provided within XI Content for software component SAP_BASIS) in order to be able to see new features in user interface when configuring communication channels.
You may check SAP Note 2276231 for details, or you can also check some SCN forum threads that discuss similar problems - for example, REST Adapter, optional parameters.
In SAP Service Marketplace, download XI Content that corresponds to release and Support Package level of your PI system (ignoring Patch Level of a specific software component)
Regards,
Vadim