Insert position

I have created an extra button in the mail form. I use the script below to insert default text into an email. In this occasion the text is inserted at the top of the email but how can i insert the text at the position of the cursor like when i use the signature option?

Sub Click(Source As Button)

Dim uidoc As NotesUIDocument

Dim body As notesrichtextitem

Dim doc_Body As NotesRichTextItem

Dim notesSession As New NotesSession

Dim workspace As New NotesUIWorkspace

Set uidoc = workspace.CurrentDocument	

Call uidoc.GotoField( "Body" )

subString1$ = ("Text to insert")	

Call uidoc.InsertText( subString1$)

End Sub