Hello mac heads...it might sound like a silly question but i just wanted to make sure,i have the usb cable that came with my touch but i noticed if my mac goes to sleep and i check my ipod touch it is out of battery,do i need a power adapter where i dont have to worry about my mac going to sleep and not charging it ...im guessing it only charges when the mac is in use??...do i have to connect to the computer directly or can i use a 2.0 hub ?