Send private message - Subject and message filled in I'm using the module Privatemsg to give users the possibility to send messages to other users on the website.

What I would like to do is:

A button on the detail page of node with type equal to Proposal, and when a user clicks on it a, they redirect to the page messages/new where the subject and message is already filled in.

Now I just have a static button on the detail page that doesn't do anything. But how can I create the functionality that they redirect and 2 form parameters are already filled in?
One way to do this is to use the Prepopulate module.  This solution is not specific to Privatemsg.  

As the module page notes:


  For example, the following URL,
  
  http://www.example.com/node/add/blog?edit[title]=this is the title
  will automatically fill the Title field on a new blog post with the
  words "this is the title". Any field can be prepopulated this way,
  including taxonomy and CCK fields. You can prepopulate more than one
  field at a time as well.