C# :: Replace Method From Synchronous To Asynchronous

Method which i use to Webrequest requests doing the job well but very slow i need to wait on every foreach item finish a lot of time. I run Execute method inside foreach statement unfortunately it takes a lot of time. I would like to convert it to asynchronous.

//this is in foreach statment and call for every request
public static void Execute(string xmlFileRequest, string xmlFileResult, string InventoryElement, string TimeOutFile, Server server)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(server.ServerIP);
request.Headers.Add(@"SOAP:Action");
request.ContentType = "text/xml;charset="utf-8"";

[Code] ....

Unfortunately i got error (Webrequest timed out)on that line:

using (Stream stream = request.GetRequestStream()) {
soapEnvelopeXml.Save(stream);
}

This is strange because i know for some elements i am expecting timeouts and i am getting them - but if they are then the line which is occuring should be: (this is without my tries) and that should be :

using (WebResponse response = request.GetResponse())

Then I am saving that element to

`sw.WriteLine(InventoryElement);` inside catch.

So the code is working ok in case my code before tries.