Does anyone know if this can be accomplished?
1) to transfer & save individual files to your computer HD.
2) and will a rom image of tennokoe bank function as it's supposed to on a flash card?
The first one will not work with the dr.neo pce flash that I have. Never tried the second one.
I'm gonna have to go with a no on this one. I'm reasonably sure that a Duo (or TG-16, etc.) wouldn't know how to write to the flash card ram, as all ram is not created equal. You could accomplish this with a real tennokoe bank, if (big if) it were feasible to build a HuCard reader for a computer.
Look for the CD-based solution called "nanami's bank" or something similar at www.zeograd.com. It allows you to view the data in an SRAM file, write it down, then burn a CD with this SRAM data on it for reloading onto the PCE.
My own program (BRAM Tool) at my site can also serve as a way to "back up" (read: visually) the data stored in an SRAM file, and then copy it back to the PCE.
There's no automated way to do this, however.