Assign bar-code automatically with variant framework

Hi,

I am new to Nav, and implementing the solution for a customer. I am stuck at a point,

I am using the default barcode mask that was in NAV assigned to a variant. The ls-retail manual says that the system will create variants and the barcodes automatically

I do see the variant been created, but not the barcodes. also when i manually create barcodes for the variants I cannot use the same Item number.

Desperately need help

Thanks in advance.