why dosent my xbox 360 pick up my sony ericsson k750i as a portable device?

[arsenalfox]

I have a xbox 360. I have a sony ericsson k750i. I have ben provided with a cable connecting my mobile to any device which has a USB socket. when i connect them the xbox 360 doesn't pick it up as a portable device as it should. i do know this works because i have tried it with another sony ericsson phone.

 

[joevsyou]

what do u think? microsoft and sony is rivals why would they want each other stuf working on there systems lol