Usage
strip.default(which.given,
which.panel,
var.name,
factor.levels,
shingle.intervals,
strip.names = c(FALSE, TRUE),
style = 1,
bg = trellis.par.get("strip.background")$col[which.given],
fg = trellis.par.get("strip.shingle")$col[which.given],
par.strip.text = trellis.par.get("add.text"))
strip.custom(...)