Rails - Jul 2006 - error_messages_for and seperate controllers

I''ve got two controllers, let''s call one Post and the other
Comment
for simplicity, i.e.:

class Post < ApplicationController
  def show
  ...
  end
end

class Comment < ApplicationController
  def create
    @comment ...
  end
end

In my create() method I would like to redirect back to the show method
after I have saved the comment.  But If I have errors in saving the
comment, how am I to display this with error_messages_for in my
template?  I would still like to redirect in this case, and not just
display the template in create().  Is there someway to pass the error
messages for @comment back to show method?  Or to pass the @comment
variable back to the show method?   Calling render :action => show
from the create method also does not seem to solve this problem.

Any sugguestions?

Appreciating all the help.  Thanks so much,

Scott Taylor