Hi I have the following piece of code to upload a file to Sharepoint. It uses HTTP PUT:
public static string UploadFile(string destUrl, string sourcePath)
No clue. But why dont you use Remote Procedure Calls (RPC) thats how i usually do it.
I found this example that might get you started http://geek.hubkey.com/2007/11/upload-file-to-sharepoint-document.html