rotated labels in barplot with beside=T and multiple groups

I have a data set that I display using barplot. I don't know what you
call it, but when I look at it, it looks like this:

lsu

(0,0.1]     (0.1,0.2]   (0.2,0.3]   (0.3,0.4]   (0.4,0.5]   (0.5,0.6]  
  A 0.052631579 0.000000000 0.000000000 0.000000000 0.000000000 0.000000000
  B 0.000000000 0.000000000 0.001007049 0.003021148 0.000000000 0.000000000
  E 0.200000000 0.000000000 0.000000000 0.000000000 0.100000000 0.000000000
   
    (0.6,0.7]   (0.7,0.8]   (0.8,0.9]   (0.9,1]    
  A 0.000000000 0.000000000 0.000000000 0.947368421
  B 0.000000000 0.004028197 0.005035247 0.986908359
  E 0.100000000 0.000000000 0.100000000 0.500000000

Now, trying the examples shown via the r-help mailing list I am trying
to make a plot where each of the groups gets displayed in a
histogram-like fashion upwards with the number 0.1, 0.2 and so forth
underneath the group. What I do is the following:

par(mar = c(6, 4, 4, 2) + 0.1)
bplot = barplot(lsu, beside=TRUE, col=colors[1:length(lsu[,1])], ylim = c(0,1.0), xaxt = "n", xlab = "")
axis(side=1,at=bplot, labels=FALSE, tick=TRUE)

NULL

nam=rep("a",10)
text(bplot, par("usr")[3] - 1.5, srt = 45, adj = 1, labels = nam, xpd = TRUE)

NULL

The result is the bars pointing upwards, like I want, but I get one
tickmark per bar, and no labels underneath. I want no tickmark, and
one label per group.

Any ideas as to what I am doing wrong?

TIA,

Karin

Karin Lagesen, PhD student
karin.lagesen at medisin.uio.no
http://www.cmbn.no/rognes/