Here I am responding to my own post......
In case anyone is interested, I opened up my USB flash memory stick, and the chip is of the type used in many MP3 players. Here is a link showing how memory was added to a brand name player http://forums.sickmods.net/index.php?topic=232
I'm not sure I understand all this, but the temptation to modify my player is too much to resist. I might try to add a 2GB chip instead of an additional 1GB. Any thoughts or additional info out there?