how to start "C:\PROGRA~1\MICROS~2\Office12\OUTLOOK.EXE" -c IPM.Note /m with C#

Question

I'm trying to invoke the email program within a c# program based on .NET Framework 2.0, so I query the Registry, get the default email program and invoke it with System.Diagnostics.Process.Start, see the code below.

RegistryKey pRegKey = Registry.ClassesRoot.OpenSubKey(@"mailto\shell\open\command");
                    Debug.Assert(pRegKey != null);

                    string path = pRegKey.GetValue("").ToString();  
                    int length =path.LastIndexOf(" ");  
                    path = path.Substring(0,length);  
                    path = path.Replace("\"", "");

                    pRegKey.Close();

                    System.Diagnostics.Process.Start(path);

The path at the last code is "C:\PROGRA~1\MICROS~2\Office12\OUTLOOK.EXE -c IPM.Note /m". I'm successfully to lunch it at the command line, but c# program reports the following error. I guess the reason is the "~" in the path, could you please let me know how to fix it (not with hard code)? thanks. 

System.ComponentModel.Win32Exception was unhandled
  Message="The system cannot find the file specified"
  Source="System"
  ErrorCode=-2147467259
  NativeErrorCode=2
  StackTrace:
       at System.Diagnostics.Process.StartWithShellExecuteEx(ProcessStartInfo startInfo)
       at System.Diagnostics.Process.Start()
       at System.Diagnostics.Process.Start(ProcessStartInfo startInfo)
       at System.Diagnostics.Process.Start(String fileName)
       ...