I finally, after almost a year of dragging my feet, got the backpacks on my second new squad of Sisters of Battle. I've another 20 left to go on, but these little things are a pain to find, and worse to lose.
Same technique as before: black primer, drybrush white, ink of P3 armor wash, ink of P3 blue ink, grey on the fleur de lis, dry brush white layer on the fleur de lis, warplock bronze on all the metal parts, white cap on the little computer screen w/ some green ink, and then bright yellow on one of the buttons, red on the other. Glue, purity seal... done.