How can I set different ringtones - one for new email and one for new SMS in Nexus One? Currently I can't find the selection box anywhere in the configuration in my Nexus One to allow this; i.e. they are the same and when I'm expecting SMS from my friend, I get distracted by the emails and vice versa...

So, is it possible everyone? And if it is please show me how. Thank you!
If I go to Message - Settings I see options to choose different ringtones. Similarly if I go to  Gmail - Settings - Main account, I can see options to choose ringtones. But I am using HTC Desire.