The partition is fine. a single partition on all the drive, primary, FAT32 (I suppose 32K cluster size, like you told).
You connected the drive in the USB Port0?
it's either port0 or port1, but not dual ports because DM will use Port0 in priority.
Then, if it still doesn't show the DIOS MIOS splash screen, it's probably because it can't mount your HDD.
I've encountered Seagate HDD with this problem, the USB interface card (inside the HDD, which convert USB to IDE) doesn't always send the correct data to DIOS MIOS.
When it sends "Hey, I'm a seagate" DIOS MIOS works.
When it sends "I don't know who I am, register me as OEM", DIOS MIOS waits for proper acknowledgment.
Try multiple times and if it really doesn't work, your drive is not compatible.