Not really an expert reply, however you can choose from within Itunes where the media goes, I copied my Itunes directory to the HD and pointed Itunes to it from within Itunes. (Preferences / Advanced)
IPhoto opens up when you click on the relevant iPhoto Library 'file' wherever it is, and I moved mine to the HD.
However I am no expert and still keep my home on the SDD to work with, and move processed, / old stuff it to the HD later.
Fine advice.
If you hold down the ALT key when you click on the application to open it (itunes, iphoto, aperture etc) it will give you the opportunity to point the app to the new location.
I agree this isn't as good a solution as i would expect from Apple. Whilst I am relatively good with tech I am not someone comfortable messing around in terminal and the like.
the solution works and, hopefully, Apple might come up with a different solution through Lion or and update to Lion?