The location of the maven project artifact along with rest of the attached artifacts is already known to maven project but cargo plugin computes the location for project deployable itself. M2E for instance provides workspace resolution, but this feature is unavailable because the computed location points always to generated jar file instead of project output directory.
MavenProject contains artifact plus attached artifacts that could be consulted first prior computing of the location if for some reason the artifact file is missing.
I'd add these new artifacts to the set of other artifacts so that as a bonus the getDependencyPath used for SHARED_CLASSPATH EXTRA_CLASSPATH would start working for all of the deployables. The only problem is how to deal with the type<->packaging logic currently located at isTypeCompatible method.