Import attachment via REST API

Hi there,

i'm currently migrating serveral redmine instances into youtrack. So far i did it with the CSV2youtrack.py-Script. Which worked pretty well.

But how can i import attachments from redmine via the REST API?
i managed it to get the response "<login>ok</login>" but after this i'll get the message

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<importReport><item imported="false"><error fieldName="MIME attachment">Field is required</error></item></importReport>

So what is the "Field" that is required?

i used the following request via node.js:

var Client = require('node-rest-client').Client;
 
var client = new Client();
 
// set content-type header and data as json in args parameter 
var args;
var cookie;
var boundary = "boundary=----WebKitFormBoundary6ECBGl5U5UnwBOqA";
var boundary2 = "----WebKitFormBoundary6ECBGl5U5UnwBOqA";
var loginRequest = client.post("http://yT-Server:8081/rest/user/login?login=root&password=******", args, function(data,response) { 
    console.log(data);
    var cookies = response.headers["set-cookie"];
    cookie = cookies[0] + cookies[1];
    console.log(cookie);
    args = {
        data: "hallo",
        headers: {
            "Cookie": cookie,
            "Content-Type": "multipart/form-data; "+boundary,
            "Accept" : "*/*",
            "Host" : "yT-Server:8081"
        }
    };
    var content = ""+boundary2+"\n";
    content += 'Content-Disposition: form-data; name="fileUpload"; filename="dummyfile.txt"\n';
    content += 'Content-Type: text/plain\n';
    content += 'Content-Transfer-Encoding: binary\n';
    content += '\n';
    
    content += ""+boundary2+"--\n";
    console.log(content);
    args.data = content;
    args.headers["Content-Length"] = content.length;
        
    client.post("http://yT-Server:8081/rest/import/test-1/attachment?test=true&authorLogin=root&created=1149678852000&file=dummyfile.txt", args, function(data,response) {
        
        console.log(data);
        
    });
});