You're right sverre, the first option doesn't work. In the Finder symbolic links made with ln appear identical to aliases, but in terminal the aliases look just like ordinary files.
What I have done on my system is set up OS X on the Original 6 G HD, however in each users Documents folder I have created an alias to the documents folder on my other 30 GB HD I have also got many other files that I am linking to on that. Not too sure about permissions though I haven't looked since the users are only myself& my fiance