cURL: multipart/form-data POST request with empty file part

Hello I'm writting a client in PHP for some CMS. I need to send an HTTP POST request with a multipart/form-data content. One of the parts is a file which must look like the request was issued after submitting a web form with a <input type="file" ...> field left empty, which is *NOT* the same as sending an empty file. This means the part should look like this in the request: -----------------------------8179530329826\r\n Content-Disposition: form-data; name="file"; filename=""\r\n Content-Type: application/octet-stream\r\n \r\n \r\n -----------------------------8179530329826\r\n Is there a way to do so with cURL ? Thanks in advance -- Emmanuel