Re: What do you do when a student is acting rudely in your class.
You might consider asking a range of the more senior students to make sure he will practice with them - each taking shifts during each class. They should keep calm and ignore his c... while training seriously and at all times letting him know that they expect him to give honest attacks to the best of his ability and follow the directions of the instructor.
You might also tell him - quietly in an unambiguously way - that he most participate in all aspects of the training including ukemi training.
Tell him that it is important in your dojo to follow the rules of dojo-kun and that you would like to help him do this. Then hand him a short written list of do's and dont's.
This is a wonderful chance to practice being a good instructor. Speaking calmly but with great authority about how you expect people to behave. If he tells you something along of the lines of 'we are doing something else' then say - calmly - "Well.. in this dojo we hold it important that all students do exactly what the sensei has told them to. so go back to that." First time you might want to add a 'Please'.. then take it up a notch at the time. If you yell at him or loose your temper I am afraid you might just add to his mischief. He needs role models that seizes the role and helps him see the borders he is currently crossing.
It's good you talk to your dojo-cho. All instructors and relevant senior students should be included in the discussion. If you all agree on how to handle him, then he will either get the message from the united group of senseis - or he will leave since he is not getting his way.
If possible I hope you will avoid kicking him out. He needs this much more than many others. Help him grow as a person if you can find the power to do so.