Hello, good question.
There is a solution for FrameMaker 10 with an ExtendScript, named "Graphic Background" in English.
The currently description is in german only (at may 2011 also in English).
Beautiful, you can set some values ... and the callout is grouped.
You can move it, or you can re-size it as group.
Download the software, currently release 048: www.finalyser.com
Open Menu: Finalyser > ExtenScript > Graphic Background