Mod_rewrite $post->$get lengths?

Im aware that rewriting a url from a POST into a GET...
....what Im wondering is if you were using post to retreive information that
was too long for a get - what happens to all the extra information in the
post that you rewote the URL of internally?


For example:

If POST to www.mysite.com/addnews
Is rewritten internally to use resource:
www.mysite.com/index.php?param1=addnews

The param is got using $_GET['param1']
The long (5 page) news article that was posted now resides in
$_GET['myNews'] instead of $_POST['myNews'].

Will the full 5 pages still be in $_GET['myNews'] or will it have been
trashed / chopped due to the lower max-length of GET requests?