Thanks for the links. Jan, thanks for the ShortRow tutorial since that is what I have decided I want to do - short row vs. heel flap.
I'll study that and see if that helps me see how to interrupt my top-down knitting, and to modify the pattern (not something I'm adept at) that I'm following from Sensational Socks. (It's a top-down, 6 stitch pattern, heel flap that I'm hoping to substitute the short row for...)
(And I'll try to come back and report.)