JRadvan,
Sorry for the confusion. Actually, Matisse4MyEclipse is still shipped separately for a variety of reasons. However, it’s very simple to get now that you’ve got 5.1 installed. Simply select Help > Software Updates > Find and Install > Search for new features to install > MyEclipse Discovery Site. Then let the wizard continue and you can select Matisse4MyEclipse. It will only take a minute to download and install.