I did it in a layout a few times, but instead of using the magic wand I used a script called amc_removeany, it is for psp and it removes all the color I have in the materials palette forground.
In psp, you scan in your writing.
then promote the background to a layer
You use the color picker tool to choose the color right off the scan itself into the forground material.
then run the script
when it's done all that is left is the writing!
here is a layout that I used it on:
http://www.scrapbook-bytes.com/galle...00&ppuser=2981
(the writing, originally was on the back of the photo)
good luck!