Danke für's Update, Erpe!
The installation description on websitebakers.com needs an update though. It still describes the activating process in WB versions prior to 2.7
Once installed go to the WB backend and activate the editor via: Settings -> Show Advanced Options -> WYSIWYG Editor.
Since 2.7 it should read:
Once installed go to Admin Tools in the WB backend and choose this editor from the editor drop down list.