Standard Output Stream of CLI

I am trying to add some kind of Interface class to an existing VB Project in order to be able to acces the IMS services.

My current solution uses the command line interface, which works pretty fine. The only problems I have are related to "im createcontent" and "im createissue". In those cases I want to know the ID of the created objects but the streamreader object in my software seems so be empty (please see code snippet)

VB.NET Code of CmdLineInterface Function:

 Private Function RunCommandCom(command As String, arguments As String) As String()

 Dim p As Process = New Process()
 Dim pi As ProcessStartInfo = New ProcessStartInfo()
 Dim output As String

 pi.Arguments = " " + "/c" + " " + command + " " + arguments
 pi.FileName = "cmd.exe"
 pi.RedirectStandardOutput = True
 pi.CreateNoWindow = True
 pi.WindowStyle = ProcessWindowStyle.Hidden
 pi.UseShellExecute = False
 p.StartInfo = pi
 p.Start()

 Using streamReader As System.IO.StreamReader = p.StandardOutput
 output = streamReader.ReadToEnd()
 p.WaitForExit()
 End Using

 If output Is "" Then
 Return Nothing
 Else
 Return output.Replace(Chr(13), "").Split(Chr(10))
 End If


 End Function

The RunCommandCom() function works fine for querys. Also calling other executables like "ipconfig" works fine. What is the difference when calling "im createcontent"? Is it possible to read back the ID of the created object with this solution?