auto skip when dowloading from huge dir

[nix4me]

I'm trying to figure out how to have lftp mirror a dir of MANY files to 
one of my server directories with many files and autoskip files of the 
same name.  I tried the -x but it didn't seem to work.  i tried like this:

mirror -x /home/phil/cvs/ /home/bob/cvs/