Adding new line item in sales document during runtime

Hi,

I have a requirement where we need to add new line item when ever the net weight is less than 50 KG.

Effected Transaction will be VA01, VA02.

Currently I have implemented the logic in below subroutine:

Perform userexit_save_document_prepare.

Using this perform new item is getting added to the document but the Pricing is not determined for the newly added item.

Please suggest, if you have came across such situation or scenario.

Thanks in advance.

Kind Regards.