GS2017 Web API - Project setup - Upload files for project creating

Hi,

I'm trying to set up a project through the web api of GS2017. When calling "/api/projectserver/v2/projects", I get a GUID as response. I assume this is the id if the new project, though, I cannot see new projects in the Project list of GS at this point. (Is this normal?)

I try to upload a source package then using this id and make a post to "/api/projectserver/v2/projects/{projectId}/files/upload". The help says:

In order to upload the files, a POST request needs to be made to ...  including a zip file containing all the project files as multipart/form-data content.

=> what field name should I use for the file content ?

This is the multipart header I use:

string headerTemplate =
"Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n" +
"Content-Type: application/octet-stream\r\n\r\n";

I tried with name=file, but I got an Internal Server Error (500) response. 

Content type is "multipart/form-data; boundary=----------------------------8d4930437814d23"

Can you please help what parameters I should use here? Is there maybe a working example code somewhere that I could use?

thanks,

Tamas