bwplot in R: adding ticks to scale, reference line, and fill bars

bwplot in R: adding ticks to scale, reference line, and fill bars

I find it difficult to find help on lattice's bwplot, and after trying
various things I thought I'll give asking a community a try. Hope there's
someone experienced out there!
I have produced the following plot http://i.stack.imgur.com/UBKpx.png, and
now I would like to:
add three more ticks to the y-axis (at 250, 750, and 1500 m)
add a horizontal reference line according to each of the six distances on
said y-axis
colour five specific ID bars (F1, F2, F3, F5, and M1), preferrably in a
light gray shade
This is the code so far, obviously there's some serious panelling missing. =S
levels(dp$period)<-c("Pre-Translocation", "Translocation")
bwtheme <- canonical.theme(color = FALSE)
bwplot(DJL ~ id|period, data=dp, main="Day Journey Length",
pch="|", xlab="ID", ylab="Distance (m)",
par.settings=bwtheme)
Any help is greatly appreaciated!
Best, Daniela