@spongeroberto
The power usb plug is just used to drain more current from the usb ports. Usb can deliver 0.5 amps, and some external harddisks need more. So, for that reason, if you use 2 usb plugs, you can have 0.5 + 0.5 amps = 1 Amp.
I have the same type of harddisk enclosure, and it works fine on the Wii with only one usb plugged in. Make sure it's the right one, or things won't work. Also make sure you plug the right one into the bottom usb port of the wii. Most usbloaders are unable to detect a harddisk on the other port.
Try it with only one plug on your pc. If it works, you know for sure you are using the right plug.
But, you probably tried all those possible combinations already. Have you checked the disk on the wii compatibillity list?
Yes, I did try that. Didn't work unfortunately. It worked fine on a laptop with just the 'data' plug. When it didn't work on the wii I added the power plug as well to see if that was the problem.
I didn't check the compatibility list before, simply because I didn't know what HD my friend had prepared.
QUOTE(PsyBlade @ Jun 18 2011, 08:44 PM) I think the 0.5A limitation is per usb controller not per usb port
try inserting the 2nd usb connector into a powered usb hub (it is not required to be connected to the wii)