Execute Process Task Using StandardInputVariable

Greetings!

I am using a Excute Process Task calling a selfwritten EXE and I'm trying to pass a command line argument to it. The code for the EXE is quit simple:

Public Sub Main()
Try
Dim info As String = My.Application.CommandLineArgs.Item(0)
MessageBox.Show("Info:" & info)
Catch ex As Exception
MessageBox.Show(ex.ToString)
End Try
End Sub

According to the help files there are two ways to pass an argument, using the property Arguments, which I guess is for hard-coded stuff, and the StandardInputVariable for passing dynamic info.

When I use the Arguments property everything works fine. I get the info messagebox with correct data. But when I leave that blank and instead use the StandardInputVariable property setting it to my package variable User::Info then I crash into an exception meaning that no arguments existed (array is out of bonds).

The variable User::Info was at first filled from a previous SSIS task and using the OnPreExecute breakpoint I verified that it contained a stringvalue. I then hardcoded a string value into the variable, but nothing helps. The task refuses to start my EXE with the data in the StandardInputVariable as an argument.

Why is this not working???