Can I make a new entry in the UseData in a LayoutDefinition

Liesje C

I have made a select grid, which shows the articles from one document.

If some rows are selected in the grid, I want to open a report which contains the articles that were selected, from the document that was selected.

In the query and in the layoutdefinition I use a parameter DocNum. If I fill this parameter with a design param value, the correct layout appears (for this docNum).

But, If I leave the design value Empty, I get a blanc report.
So, it seems that the parameters DocNum is not given to the report.

I think I have to add an enrty in UseData in the layoutDefinition.
Is this possible?

Or, is there an other way to pass the parameter from the selectGrid to the parameter of an own layoutdefinition

Thanks for the suggestions
L