What to do with star developers who don't document their work?

There is a colleague who seriously knows his stuff, he is one of the brightest I've ever worked with, but he:

works in his own little area of his home directory rather than in the common CVS repository
doesn't document his code
doesn't comment his code, e.g. 3,500 SLOC of C with no comments and no blank lines to break things up
often overcomplicates things, e.g. uses three shell scripts that call one another to do the work that one simple shell script could do.

Maybe this possibly is one of those people who thinks "if I'm the only person who knows this, they can't get rid of me"?

Any suggestions on what to do?

BTW Management knows about the situation and are trying to change things.

Solution

In my opinion somebody doing such stupid things as you have described above can't be a star developer! To me it seems like he intentionally makes things more complicated as they are, so that nobody else than himself can maintain the code. This makes himself more important than he really is! Talk to him. He has to change it! If he doesn't, replace him with a real star-developer!

I promise you, in even half a year he will not know how his own code works! Fire him and you can save a lot of time and money.