Nope, here's what I did for each one. I was just following the documentation on adding custom fields. What else do I need to do?
<Browsable(
False), BusinessFieldDisplayInEditor(), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)> _
Public ReadOnly Property [DebtorName]() As System.String
Get
Return Me.ExecuteScalar("SELECT Name FROM Debtors WHERE DebtorKey=" & DebtorKey)
End Get
End Property