The function to create a post will have a little twist because it will have to set the author of the post. It will take, among other information, the name of the author. We will then retrieve the author's object by using the manager's search function.
public static function createPost(authorLogin : String, title : String, body : String) : hxBlog.Post
{
var author = hxBlog.User.manager.search({username : authorLogin}, false).first();
var p = new hxBlog.Post();
p.author = author;
p.title = title;
p.body = body;
p.postedOn = Date.now();
p.insert();
return p;
}