number range for billing document

Hi experts,

I have created range object and assign number range for range object through SNRO......

As i have created number range for BUKRS(AB08)......

when i go to VF01 TO CREATE BILLING DOCUMENT and put OUTBOUND DELIVERY NUMBER there and save.......

i got following message.......

A:ZMM:999 Number Range Not defined ,Please maintain with tra

So my confusion regarding field...as i use BUKRS....

i have created company

2000 sales organization

AB08 company code

As i am stuking for invoicing till OUTBOUND I created every thing now for invoice through VF01 i get the above error message...

please provide me the exact solution for this problem....

thanks

babbal