ipod and itunes problems synching "my ratings"


I just traveled for an extended period of time without my computer, but with my ipod. during that period i spent an extensive amount of time rating my songs on my ipod-i assumed that the ratings in my itunes library would change once i hooked in my ipod (when i returned to my computer today)-but this was not the case.
Is there any way to synch up the "my rating" between my ipod and itunes library?