A lot of times with external drives. they are just normal drives tossed into a case that has a usb interface.
THIS WILL MORE THAN LIKELY VOID THE WARRANTY I TAKE NO RESPONSIBILITY heh...
you could potentially remove the case. remove the drive. if it's compatible with your PC. more than likely it is, it would be ide... plug it up and run smart that way.
i had Google around for usb smart versions and notice what you mean, sorry I've never owned a external drive. usb just seems slow to me. and i always fear things might happen,,, like me dropping the enclosure lol
there's a usb version of the software i pasted a link to, it says specifically maxtor and 2 other drives. I doubt it would work, but might be a last resort type option...
tho honestly if it's still under warranty, might just want to send it back.