WordPress comments plug-in needed

We are looking for someone to code a WordPress plugin that provides an XML-RPC function to post comments. The plugin should only accept calls from a certain IP address, or a list of IP addresses. Parameters will be: - the URL of the post where this comment should be added - the ID of the comment in our system and the regular comment fields: - name - email - url - comment The plugin then needs to ping back the comment ID to our system, as soon as the comment has been published or deleted. This urgent, so please only bid if you can start right away. Thanks