Graham SupAlpuket You can but you have to be using the full page code editor NOT the code blocks in the building tool it has to be the the full page code editor
I used this to test

<script> var foo = "<pre>These\nare\nnewlines.</pre>"; document.write(foo); </script>

and heres the output
http://graham99.xtgem.com/Anl
I am not sure if anything can be done for building tool code blocks but I will ask tomorrow