Sending an object to a form

[Frode]

I've written an add-in for MS Word which adds a commandbarbutton, and fires a form when clicked.

I'm having some trouble sending the Word application object to the form, so that it can work with my Word document.

Conceptual code looks like this:
file: connect.vb

public class
        Dim withevents SuperForm as Windows.Forms.Form
        Dim applicationObject as Object
         applicationObject = application

       private sub button_click(ByVal Ctrl As Microsoft.Office.Core.CommandBarButton, ByRef CancelDefault As Boolean) Handles Button.Click
            SuperForm = New Mainform
            SuperForm.Show()
        end sub
end class

file mainform.vb

Private Sub MainForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

       Dim oWord As Word.Application
       oWord = CType(applicationObject, Word.Application)
...

How can I send the current Word application object to the new form I'm creating?

Is is correct to use something like this?:

Public MainForm(ByRef applicationObject As Object)
and 
SuperForm = new MainForm(applicationObject)