Some MP3 players are mass storage compliant and will work fine on anything. My Creative MuVo is, it shows up as a 1GB drive. However, the SanDisk Sensa that I bought my mother does not; it shows as an MP3 player.
You are going to have to use the software that came with the T30 to transfer your songs, etc. And don't get all hissy about it; Apple is the same with iTunes and the iPod. You can't use anything else (legally, at least) to get stuff on and off it.
I recently purchased an iRiver T30 thinking "It's a USB mp3 player. So I'll just plug it into my mac and OS X will see it as a mass storage device."
Survey says: XXX
Apparently something in the players firmware that makes it plays for sure compatible makes it unusable as a USB Mass storage device.
Is that essentially correct?
And if it is; who's the brainiac who thought of that?
Grrrrrrrrrrrr

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic