Are these songs legit or pirate?
I think itunes will not transfer limewire pirated songs to your ipod, due to copyright issues.
What you need to do is use the winamp program with the ipod plugin which enables you to upload and download any songs to and from your ipod to winamp collection.
No need for stupid itunes at all!!
Your ipod finally becomes useful !!!
http://mlipod.sf.net
http://winamp.com/plugins/details.php?id=138888