Somewhere I got a ZPC: device which uses fat95 and allows the Amiga to see Windows-formatted Zip disks just fine.
What you did with GVP tools was create an Amiga filesystem in an RDB-partitioned Zip disk, which Windows does not recognize (though, I believe UAE will recognize it; I don't know as even though I have Amiga Forever, I still don't do Amiga emulation.)
