It may be unrelated to this matter, but with Swing applications I sometimes needed to specify an extra flag with the Apple Java 1.6 version to show the menu properly on my Mac.
Specifically, try adding
as an argument in the product file (of your swing client) under "Launching", "VM arguments".
Then go back to the "Overview" tab, click "Synchronize" and then launch the app.
which is probably the same as yours, and recommended when using Aqua LAF on OS X with Swing.
My Test Results: no parameter or Dapple.laf.useScreenMenuBar=false
=> the menu appears as expected inside the Swing Frame.
=> but not all menu items are clickable, sometimes the "Extras" menu disappears
* The menu bar does not properly in the exported product (swing)
* An empty menu (Tools for me) disappears in a certain case: If i click on "File", and try to move the selection with released cursor over to the 'Tools menu'. (Instead of the blue background of the 'hover/selected' state, the menu title disappears)
Mac OS X 10.7.5, Java 7 (oracle 1.7.0_13)
Eclipse Juno SR2 RC3 development build, Scout 3.8.2. (Downloaded as instructed in this thread.)
The exported ini-File seems to be properly exported and contains the useScreenMenuBar flag.