Need to create a message INVOIC from transaction MIRO

Hy,

try to find an answer on following prob.

I need to send the billing information from transaction MIRO to another system. They want to have a INVOIC02. I know how to create a message but i have not found a solution (wich function) to create a INVOIC02 with all information.

Any help ?? Is there another solution or do i have to develop the filling of the IDOC ?

Thanx

Jens