Add new record automaticaly in grid type form

Hi, is possible add a new record in a grid for form master - detail ?

When i insert a new record the master, it saves record and add a new record to detail. (without insert a record phisycs to db)

for example a propterty autoinsert into detail or a macro sc_autoinsert(‘grid_detail’);

Why should that be done ?
You could add a new master without having something in the detail !
What should be inserted ?
Take an invoice for example:
you create the master, and you have to insert the positions, so what?s wrong ?

I have an invoice (mater - detail).
When an user insert a record on master, i need that SC insert a record on detail in buffer, so the user every time make a new invoice, do not clicked the button insert new on detail. (the idea is to speed up the process) an invoice always have at least one item.