Hi Tom, I've not used the DasMikro devices before, so I can't speak from experience.
But I do know that the Mini firmware needs to match the version of Flash you're using. So if you're using Flash V4 then the firmware on your DasMikro Mini needs to be whatever version Thomas has that will work with Flash v4. Maybe DasMikro ship them with old firmware. When (if) you can connect to the device with Flash, the Mini's firmware version will be shown on the Diagnostic tab. Under the Modul drop-down menu at top there is also an option to update the Mini firmware, but I don't know if this works anymore, since I assume Flash goes out to the internet to Benedini's website to get the firmware.
If it is a firmware issue, and you can't update the firmware on the Mini, then I'd try looking for a place to download somewhere the older V3 version of Flash, and maybe that will work.
I really think DasMikro shouldn't be selling hardware that they can't also provide the firmware and software for, because without those the board itself is not of much use.
Finally, there are not many people here reading these posts. There is a very long thread on the DasMikro boards over on RCTankWarfare, I'd recommend trying to ask your questions over there where more people might see it:
Dasmikro (TBS Benedini clone)