Sets HTTP request header.
var value = obj.getRequestHeader(name);
obj.setRequestHeader(name, value);
name (string) - header name
value (string) - header value
var req = new AW.HTTP.Request;
req.setURL('/application/service.asmx');
req.setRequestHeader('Cookie', 'c1=value1; c2=value2'); // set 'Cookie' header
req.request();