Saving multiple lines related to a Document Line

Hi all,

does anyone has any idea how to do this?

I'd like to save data related to each row of a SalesOrder

in the same way a userfield added to a line is saved

automatically with the order

(that is in the same "run unit").

The problem is that my data are a matrix:

for each SO line I have to save many lines (no fixed number) with 2 columns.

The idea is the same of specifying which batch numbers

I ship in each delivery line: for each line I can specify

more than one batch number.

With user defined fields I can only add columns to a line.

Is there a way to do it?

TIA

francesca