BB ID doesn't transfer BBM contacts to my new device

Hi, how are you? I've got the following problem:

I have BBM 7 on my old device (Bold 9780, OS 6), and want to transfer my BBM contacts to my new device (Curve 9320, OS 7)...

I had BB ID on my old phone, and when I log in with BB ID in my new phone, my BBM contact list is empty...

How can I transfer my BBM contacts to my new phone?

THANK YOU! :D