Put simply, "documenting stuff" happens a lot. Documentation is an important part of software development (funny link about software documentation), so it is best to learn how to do it early in your career. Further more Furthermore, the best way to handle these kinds of projects (which from what I have seen is a common occurrence) is to pour through it and document what it does.
As to your specific question, I think you are missing the point. You should not be trying to find a way to get management to have someone else do your job. As you progress through your career, people will see that you are that person that avoids real work like the plague. Your career will be filled with tasks that you do not want to do (I am avoidavoiding a couple right now, for instance). They still must be done.