How can I add custom fields to be prepopulated on "Get Items From"

Here is my scenario:

I have added custom fields to Quotation Item and Sales Invoice Item . These are all float fields that contribute to the total for the line. What I want to do now is get these fields also fetched and populated when a user clicks on the Get Items From button.

How can I do this using custom scripts or server scripts?


Read the last post in this thread :

Change the trigger to the button and so on