Liviu
Have you tried to use \SweaveOpts{echo=T} for the with_code document, and 'echo=F' for the document with no code? You can also use this option on specific chunks as follows <<echo=F>>= @
I have used this in specific chunks but it isn't practical for a full report. Howver, I haven't tried it as an option in the pre-amble. I will give it a go.
Thanks, Graham