System.Diagnostics.Process.StandardInput not defined.

I recently tried creating a script for starting another process and communicating with it. It seemed to work fine and everything compiled, but unity's console complained giving the following error:

 Assets/FTPUpload.cs(99,36): error CS1061: Type `System.Diagnostics.Process' does not contain a definition for `StandardInput' and no extension method `StandardInput' of type `System.Diagnostics.Process' could be found (are you missing a using directive or an assembly reference?)

Since I can easily locate StandardInput in the script, and it compiles fine, I'm stumped. And I would like to know if anyone else experience the same problem? Or know of a workaround / solution.

To recreate simply try this small script StandardInputTest.cs:

 using UnityEngine;
 using System.Collections;
 using System.Diagnostics;
 
 public class StandardInputTest : MonoBehaviour {
     void Start()
     {
         Process test = new Process();
         test.StandardInput.WriteLine();
     }
 }

Thanks in advance!