For Line Style you enter Solid, for Foreground Color you can choose a color from the list. In the section Design you enter a name for the element. Under Layout you first set the Width. Then you state the End Band, meaning to which band the cross band line should go, as well as the Start Band, meaning where the line starts. You can also define the Start and/or End Point with coordinates.

 

These were the configuration options of the cross band line.