Bolding the menu item seems to be possible with ComDefaultItem.
But it has the sideeffect, that the view gets activated, if you double click on the menu, you put it in.

Here is what i came up with to use ComDefaultItem, which seems to be working.
Code:
Function CreateCommandBarControl Handle hoControls Integer eType Integer iId Boolean bInCreateTempInstance Returns Variant
   Variant vControl
   Handle hoCommandBarItem
   Get ComAdd of hoControls eType iId "" Nothing bInCreateTempInstance to vControl
   Get Create (RefClass(cCJCommandBarControl)) to hoCommandBarItem
   Set pvComObject of hoCommandBarItem to vControl
   Set ComDefaultItem of hoCommandBarItem to True
   Send Destroy of hoCommandBarItem
    Function_Return vControl
End_Function
just added that to the one cCJMenuItem I wanted to be bold. I read, that you can do that also with multiple menu entries, but I don't know, how it then works with the double click on the menu.