Plater settings window does not allow setting skirt/brim

[Lenbok]

My normal profile has brim set to 0, but I sometimes want to turn on the brim on a per-print basis. It should be possible to do this in the plater settings window by adding an object modifier, but none of the skirt and brim settings appear in the list of settings to add.

This is with Slic3r 1.1.5

[alranel]

Brim settings can't be overridden on a per-object basis. You can set them in the Print Settings tab.