This feature allows the application of numbered or lettered exhibit stamps to existing PDF documents in Adobe Acrobat.

Place this file in C:\Users\USERNAME\AppData\Roaming\Adobe\Acrobat\11.0\Stamps, or for WinXP in C:\Documents and Settings\USERNAME\Application Data\Adobe\Acrobat\11.0\Stamps (choose the folder for your current version of Acrobat),
then restart Acrobat. 
 
---------------------- Using the Dynamic Exhibit Stamp ----------------------
1) Choose Comment, Annotations, Stamp Tool (you can also add it to your toolbar)
2) Click the Stamp Tool
3) Choose the Exhibit Stamp Category
4) Choose a stamp and click to place it on the document
5) Enter the Exhibit Number
6) The stamp will be placed on the document.
Instructions can be downloaded here.