create a procedure for the event that you want handled by the dynamically created button (it must have the same signature as the event you want handled), then use an addhandler statement.
Private Sub SomeProcedure(ByVal sender As Object, _
ByVal e As EventArgs)
'code for newbutton goes here
Dim newbutton As Button
AddHandler newbutton.Click, AddressOf SomeProcedure