RubyInline, RDoc comment for C inline method

Hi,

I am playing around with RubyInline and want to include
a "inlined" C method to the API documentation generated by rdoc.

Here is an minimal example:

---- a.rb ----
require 'inline'

class A
  # Method A.a1
  inline do |builder|
    # Method A.a2
    builder.c %{
      /*
       * Method A.a3
       */
      int a() {
        return 0;
      }
    }
  end

  # Method A.b
  def self.b
    0
  end
end
---- end of a.rb ----

Calling "rdoc a.rb" generates only the documentation for method
A#b, not A#a.

Is it possible to let rdoc generate the documentation for A#a?
If so, how?

Daniel