how can i add more than one partition into the virtualbox guest XP?

hi,
i am using virtualbox 4.0.2 and i have created guest XP sp2, but i have problem to create more than one partition. i don’t no how can i create partition. when i open virtualbox than see only one partition C:, and one cd/dvd drive which is D, so how i add anothere partition on it. please help me for solve this.