how to define new message/generate new header in rosserial_arduino

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Hi, I kept searching through the wiki but this page was not created yet (http://www.ros.org/wiki/rosserial/Tutorials/Adding%20Other%20Messages) and I can't try it out myself, so I'm going to ask here.

in this link(http://answers.ros.org/question/11023/rosserial-and-custom-message-cannot-load-package)brice rebsamen says there's a script generating new msg type for me, where is it?

say, I want to define a new msg type new_msg::New, to publish it from PC to arduino. while I got New.h in package new_msg with the command "make" under the package, this New.h is not suitable for arduino liberary. I need a New.h file that tell arduino what the message looks like. What should I do? Thank you in advance!