Add Region using .NET and late binding...

I am trying to create a Region with .NET. I am using late binding since I have to program to 3 different version of AutoCAD.

The following code works:

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

       Dim V_Region As Object

       ' declare variables
       Const PI = 3.14159265358979
       Dim line1 As Object
       Dim line2 As Object
       Dim line3 As Object
       Dim arc1 As Object
       Dim center1(2) As Double
       Dim point1(0 To 2) As Double
       Dim point2(0 To 2) As Double
       Dim point3(0 To 2) As Double
       Dim point4(0 To 2) As Double

       point1(0) = 10 : point1(1) = 10 : point1(2) = 0
       point2(0) = 50 : point2(1) = 10 : point2(2) = 0
       point3(0) = 50 : point3(1) = 20 : point3(2) = 0
       point4(0) = 10 : point4(1) = 20 : point4(2) = 0

       line1 = V_AutoCad.ActiveDocument.ModelSpace.AddLine(point1, point2)
       line2 = V_AutoCad.ActiveDocument.ModelSpace.AddLine(point3, point4)
       line3 = V_AutoCad.ActiveDocument.ModelSpace.AddLine(point4, point1)
       center1(0) = line1.EndPoint(0) : center1(1) = line1.EndPoint(1) + 5
       center1(2) = 0
       arc1 = V_AutoCad.ActiveDocument.ModelSpace.AddArc(center1, 5, 3 / 2 * PI, 1 / 2 * PI)
       ' make array for region
       Dim arrayobj(3) As AcadEntity
       arrayobj(0) = line1
       arrayobj(1) = arc1
       arrayobj(2) = line2
       arrayobj(3) = line3
       ' make the region from the array

       V_Region = V_AutoCad.ActiveDocument.ModelSpace.AddRegion(arrayobj)
      

   End Sub

But when I change this line:

Dim arrayobj(3) As AcadEntity

To:

Dim arrayobj(3) As Object

I get "Invalid Object Array" on the AddRegion line.

Does anyone know how to fix this and stay as a late binding program???