k3b mesure of dir size across nfs

[pol <linux_milano@yahoo.it>]

Hi all, 

I use k3b to burn backup cd  (dvd-r 4.7 gb) of directories on ext3 file
system across nfs connection. 

K3b has just reported the selected remote directory to be more than 2 gb
large. Yet the same mounted directory, as measured by 'du -s' on the local
station, where k3b is running, returs about 0.5 gb only . That is the
probable correct value, being the same that is found by 'du -s' on the
remote machine. 
How to fix that strange k3b behaviour?

thank you 

--
Pol