Debugging Gotcha With .Net's System.Diagnostics.Debugger.Break()

In developing a SharePoint feature deployed at web application scope, I was trying to attach the debugger to the w3wp.exe process so I could see what was going on in my code. I used the iisapp command to try and pick the logical process... no dice. So then I connected to ALL of the w3wp process (there were 5 for them). It still wouldn't hit my breakpoint. So then I threw a

System.Diagnostics.Debugger.Break();

statement into my feature's code. When the feature activated, as expected I was given the option of selecting the debugger I wanted to use. So I chose my current VS2008 session. And here's the kicker--the next thing that happens is a dialog pops up telling you that "There is no source available at the current location". Now I had already dealt with all kinds of problems with missing symbols getting to this point, and I thought this was just the next level in the rathole I had been down on that issue. I was about to give up, but then I notided that the Call Stack pane was actually showing that the process was stopped down inside the System.Diagnostics assembly (which makes sense). All I had to do was a Debug > "Step Out" and I was back in my code, ready to debug.