It is a tangled web. I noted from your post that the client IS filing. i.e., the re-org plan has not been approved by the court. Most definitely, you will have to make a claim, as is the case with every other creditor. You will definitely need the services of an attorney well-versed in the bankruptcy code (Chapter 11 of the United States Code). In perusing Lexis, there are about a 100's of sections in the chapter. In a quick reading, as a creditor, you can petition to have your debt set-aside - away from the proceedings. Of course, you will have to make a persuasive argument to the bankruptcy judge.

The bottom line, how well you navigate the waters will determine whether you can make the most of your rights...

Good luck...