[HTTP] Force multipart/form-data without having to call addPostFiles().

I have two questions: I am trying to make an HTTP request to a server that expects multipart data, but this particular request does not have a file attached. I noticed that when I set the method to post and call just addPostFields, it encodes as application/x-www-form-urlencoded, but when I call addPostFiles to add a file, it encodes as multipart/form-data. Is there a way to force it to use multipart/form-data even without calling addPostFiles? I'm looking at the source code (http_request_body_fill in http_request_body_api.c, version 1.7.0b1), and I can see logic like this: if (files present) { multipart encode fields and files } else if (fields present) { url encode fields } else { ... } So it appears that there is no way to force multipart data... is this true? If so, it's incredibly frustrating, because the feature I need is right at my finger tips but I can't get to it through PHP. I can see the logic in the source that would need to be changed to make that happen, but a custom PECL build is not an option, unfortunately. What's the best way to send multipart data without a file attached? My second question is: Is there a way to send multipart/form-data encoded post requests when the data for the file is in memory (e.g. posted to a PHP script and you are echoing it to another server) rather than in a server-side file? Thanks! Jason