Let's say you want to augment the SysML Requirements diagram pallet by adding three new buttons for DSL element types: one – for the User Needs element type, other – for the System Requirement element type, and another – for the Component Requirement element type.
Open for edit the customization profile.
Create a Profile diagram or just open an existing one.
Create a customization.
Set the DSL element type as the customization target.
How can I simply set the customization target?
Drag the DSL element type to the shape of the newly created customization element.
Create the Place on Diagram Pallet attribute for the customization.
How can I create the attribute?
Open the Specification window of the customization element.
Select Attributes on the left side of the window.
Click the Create button and then select Place on Diagram Pallet (see the following figure).
Type the new attribute name (this is optional, since the name is not visible anywhere in UI, except the attribute Specification window).
In the Specification window of the Place on Diagram Pallet attribute, select the cell of the the Place property value, and click .