I believe the code you're looking for is:
Code:
<Element ID="ToolbarFieldMain_LevelMeter_Left_Cap" X="10" Y="10" Width="1" Height="1"></Element>
<Element ID="ToolbarFieldMain_LevelMeter_Right_Cap" X="10" Y="10" Width="1" Height="1"></Element>
<Element ID="ToolbarFieldMain_LevelMeter_Mid_Left_Cap" X="10" Y="10" Width="1" Height="1"></Element>
<Element ID="ToolbarFieldMain_LevelMeter_Mid_Right_Cap" X="10" Y="10" Width="1" Height="1"></Element>
Those lines belong in your Toolbar panel file, within the ToolbarField element.
rushl