Printing VBRK-XBLNR on Billing

Hello Gurus,

I have copied standard smart form LB_BIL_INVOICE as ZLB_BIL_INVOICE1 and attached it in NACE.

After that added a text field under INFO_REFERENZ_RECHNUNG as Reference.

Attached the field vbrk-xblnr.

But when Run the program value or vbrk-xblnr is not appearing.

Please suggest, what I have to do.

Thanks.

Dev