samba - Sep 2005 - Rsync & cifs or smbfs - cannot update modification date with cifs

I use rsync to update files to a samba shared folder on another 
machine.  If the remote drive is mounted as smbfs in fstab:
//xx.xx.xx.35/YellowDog /mnt/mic smbfs username=xxx,password=xxx

Then everything works fine.  However if I mount it as cifs & run rsync, 
the date/time on the remote files is that of the transfer, not of the 
original file creation/modification date.  Therefore rsync transfers are 
messed up because it uses the date to work out if a file should be 
copied or not.  Local machine is debian sarge, remote system is OSX 
10.3.  Using smbfs works fine & the dates are correctly preserved across 
to the remote machine, but I understand that cifs is the way forward, so 
I'd like to get it working with cifs.  What am I doing wrong?  The 
remote directory & files are owned by the username specified in fstab, 
and are permission 755 (directories) or 644 (files).

The rsync command line I'm using is rsync -rt --delete --modify-window=1 
/source /mnt/mic.

Thanks!