[R] trellis: left-aligned text in strips?

[RINNER Heinrich]

Dear R community,

by default, text in the strips of a trellis plot is centered in the
strip.
Is there a way to have the text left-aligned?

for example:

libary(lattice)
test <- data.frame(x=rnorm(100), y=rnorm(100), a=rep(c("A: centered
text","B: centered text"),50))
xyplot(y ~ x | a, data = test) # ok, strip text is centered
test <- data.frame(x=rnorm(100), y=rnorm(100), a=rep(c("A: left-aligned
text","B: left-aligned text"),50))
xyplot(y ~ x | a, data = test) # how???

I am using R 2.6.2 on Windows XP, package lattice Version 0.17-6.

-Heinrich.