I recently posted a method of twisting Keynote Legends around to do exactly what you want. However, maybe using Note Blocks with numbered notes would better suit your documentation process?
Read more at:
Using Note Blocks for Numbered Notes – WikiHelp
Also check out my 2009 post:
What Revit Wants: Note Blocks – What are they??
We do a lot of basic scope-of-works drawings for heritage work that sometimes just involves imported JPGs on drawing sheets and I've found this method to work very well with a couple of filters setup in schedules to ensure the right elements appear on the right sheets.