Anyways: Does it work for "inl" files??? It really should. I see no reason why it should not work if you add this extension to the "source files" category that way.
I tried a test on mushakk's behalf.
I defined an inline function in a .inl file, included it, and called it with a breakpoint.
I got the same results when adding "*.inl" to both Headers (what i think is the common practice) and Sources (what you suggested).
The debugger halted at the correct place, but did not open the file. Double-clicking that function in the call stack window also did not open the file.