Copy a document from DB to Task in Maildb

I have the need to copy a document in a db to a new task in the users own maildb and have below script for it.The script creates a task in the maildb, but copies the whole content rather then filling the fields of the task form with the data in the form to be copied. Please, what am i doing wrong?

Sub Click(Source As Button)

Dim session As New NotesSession

Dim db As NotesDatabase

Dim mailDb As NotesDatabase

Dim collection As NotesDocumentCollection

Dim newsletter As NotesNewsletter

Dim doc As NotesDocument    

Set db = session.CurrentDatabase

Set mailDb = New NotesDatabase( "", "" )

Call mailDb.OpenMail

Set collection = db.UnprocessedDocuments

Set newsletter = New NotesNewsletter( collection )

If ( collection.Count > 5 ) Then

	Messagebox( "Please select five documents or fewer" )

Else

	For j = 1 To collection.Count

		Set doc = newsletter.FormatDocument( mailDb, j )

		Call doc.ReplaceItemValue _

		("Form", "Task")

		Call doc.Save( True, True )

	Next

End If

End Sub