Richard,
Didn't see this posted here.
I am not clear on a few things:
1) are the separate photos each on their own layer using their own layer mask? This is a rather fine point...you are using one mask for each layer?
2) Which tools are you using for the mask: free tools or the ones in the book?
3) I am not sure where you are painting the black without knowing the answer to #2, but it seems you want some black on the masking as well as on the image?
Please let me know. Posting a screen shot of the setup would help tremendously if you can...or send as an attachment to:
rlynch@pledgemaker.com