Use a large piece of lace (or even a tabletop paper lace) as a stencil on some areas of the pants and dab the fabric paint on to it, then peel or the lace off and VOILA! Lace print on your pants!
I've done it with my airbrushes for a friend that wanted the "fade in or out" look. After that, topstiched on some zippers in diagonal directions.
I never heard any complaints from her.