Data labels in barchart (lattice)

Dear all,

I use the barchart-function (lattice) for plotting stacked barcharts. 
The data is a summary table (data frame) of likert-scale-evaluations 
(strongly agree, agree...strongly disagree) to different issues 
constructed as follows (L1=precentage of "strongly agree" evaluations, 
L4=precentage of "strongly disagree" evaluations):
---
ID	L1	L2	L3	L4	DN
Issue1	25	40	35	0	0
Issue2	15	30	22	28	5
.
.
.
---
What I have so far not achieved is adding data labels to each "sub-bar" 
of a 100%-bar. What I would like to have is something like this:

Issue1: |###25%###OOOOOO40%OOOOOOXXX35%XXX
Issue2: | (similar)
...

What should I do in oder to display data labels?

Thanks in advance,
Kimmo