Populating file fields with an http-request with the Services module and a REST Server (Drupal 7)

Question

I need to add content trough a node.create and one of the fields in the content type I am adding is a file field. So far I have been able to get my Services module set up with REST server to accept user and node resources and I have been able to make http-requests to add content containing text fields. Now I need to expand on this to work with a file field but I have not been able to find any resources about creating nodes that contain file fields. I am wondering how would this be done? Would it be done in one pass or two? Would I upload the file with a first post then do the association next? Does anyone have any good resources related to this topic?