The article says this:
"AfterDropBuild: Called after dropping the built binaries, build log files, and test
results to the release server. Insert your task into this target to run
custom tasks after the built files are saved to the drop directory."
This is incorrect: the build log files will not be available when this target is run. They are copied after the MSBuild project exits so you won't be able to do anything with the log files by overriding any of these targets.