Thank you for your post dserodio.

On JUDE, you can add the "subsystem" stereotype to a package and vice-versa.

Here are two methods to add the "subsystem" stereotype to a package.

Method 1 :
1. Right-Clicking on a Package to open Pop-Up Menu in the Diagram Editor then select [Add Stereotype].
2. There will be <<stereotype>> showing up on the top inside the package element, then Double-Clicking on it and you can directly type "subsystem" in.

Method 2 :
1. Select a Package in the Diagram Editor or Structure Tree View.
2. Go to the Property View (It is the left bottom panel). then select [Stereotype] tab.
3. Press [Add].
4. Scroll to the "Subsystem" to set it or type "subsystem" in directly.

You can do vice-versa with same step.