PS2 recognises USB drive but PS3 doesn't?

I'm trying to copy over saves form my PS2 MC to the virtual MC on PS3. I sucessfully used ulaunchELF to copy the saves onto my USB drive. Yet when I used the same USB drive to boot ulaunchelf on my PS3 the MASS drive shows up empty!!!

I can boot any .elf files fine, it's just ulaunch (on the PS3) seems to think the USB drive is empty. But the EXACT same drive on a PS2 works fine - I can see all the folders etc.

Just to clairfy, I'm using the same USB drive with the same ulaunch.elf file on both systems. Except the PS3 booted-version doesn't see the mass drive. Even though it was booted from it. :(

Any ideas?

The normal usbd.irx isn´t compatible on the ps3 for some reason.
try this one.
it´s compiled with the same usbd.irx that OPL uses for the ps3.
Now your good to go and you saved the money you would have spent on a memcard adaptor;)

Thx man, I'll give it a try and report back.