How to make toolbar items with a on/off state ?

I need "old style" toolbar items that keep a "pressed" state…
setView method
i.e. in
- toolbar:itemForItemIdentifier:willBeInsertedIntoToolbar:

do something like:

[toolbarItem setView:aButton];
[toolbarItem setMinSize:NSMakeSize(NSWidth([aButton frame]), NSHeight([aButton frame]))];
[toolbarItem setMaxSize:NSMakeSize(NSWidth([aButton frame]), NSHeight([aButton frame]))];
Use the standard NSToolbarItem with a button, and use the