Maven handles it this by copying a *-sources.jar to the repository. As an example, here is the Maven repo for acegi-security: http://repo1.maven.org/maven2/org/acegisecurity/acegi-security/1.0.7/ with the relevant source jars.
All common java IDEs have support to automatically attach the source code inside the IDE if it exists.
I guess two things need to happen:
1. There needs to be a way to package the source (either inside the binary package or alongside it)
2. Visual Studio needs to be able to bind to this source. See http://stackoverflow.com/questions/2620279/visual-studio-attach-source-code-to-reference. Like many things, it seems this functionality is not native to VS, but ReSharper adds it.