How to pass an uninitialized array from VB6 to .NET via COM?

I want to replace a component written in VB6 with a new component written in VB.NET. The new component has to work with other VB6 applications until these are replaced as well. I'm having trouble with a function that takes string arrays as parameters.

I'm using a VB6 class that contains this function to replicate the problem:

Public Function MyMethod(arr() As String, arr2() As String, Result$) As Integer     
    Result = Join(arr, ", ")
    MyMethod = 0        
End Function

I can successfully call it from an test program (VB6) like this, which displays "Hello, World":

    Dim obj As Object
    Dim arr() As String
    Dim arr2() As String
    Dim result As String

    Set obj = CreateObject("MyHelloWorld.MyClass")
    'Set obj = CreateObject("HelloWorldCOMNet.MyNetClass")

    arr = Split("Hello World", " ")
    'ReDim arr2(0)
    result = ""

    If Not obj.MyMethod(arr, arr2, result) Then
        MsgBox result
    End If

I can't modify the actual VB6 application, but I want to replace the VB6 ActiveX component with class written in .NET. The new class looks like this:

<ComClass("cd74ab4a-76ca-4c84-9f49-147e6f6ac01f", "b3314f71-cb8d-48ea-bfe6-9d1995aa4f58", "40c30052-0cc8-4ef6-b1e8-92e4ddbcb515")> _
Public Class MyNetClass

    Public Sub New()
        MyBase.New()
    End Sub

    Public Function MyMethod(ByRef arr() As String, ByRef arr2() As String, ByRef result As String) As Short
        result = String.Join(", ", arr) + " from .NET"
        Return 0
    End Function

End Class

I test it by replacing Set obj = CreateObject("MyHelloWorld.MyClass") with Set obj = CreateObject("HelloWorldCOMNet.MyNetClass") in the test application.

I used a breakpoint in the constructor of the .NET class to verify that it has been executed.

When the test application calls MyMethod, a FatalExecutionEngineException occurs.

I narrowed the error down to the second parameter arr2. When I initialize the variable using ReDim arr2(0), the .NET code works. So my guess is that it's related to the fact that this variable is uninitialized. Unfortunately I can't modify the actual VB6 application.

I compared the method signatures using OleWoo and they appear to be the same (except for the id).

How can I modify the signature of the .NET function to accept uninitialized string arrays?

Edit: Output from OleWoo:

[id(0x00000001)]
short MyMethod(
   [in, out] SAFEARRAY(BSTR)* arr,
   [in, out] SAFEARRAY(BSTR)* arr2,
   [in, out] BSTR* result
);