I\'ve just started playing with Xcode 4, and found that, no matter how I setup debugging symbols in the project, Instruments refuses to display source lines for stack trace item
In newer versions of Instruments (I have 5.1.1 (55045)), you can add additional paths to be searched for the dSYMs and source code
5.1.1 (55045)
Open up Instruments' Preferences, then click the "dSYMs And Paths" tab.
Then add your path to the list.