Create a layout file with the panel contents:
Sub CreateNewPanel (Width As Int, Height As Int) As Panel
Dim p As Panel
p.Initialize
p.SetLayout(0, 0, Width, Height)
p.LoadLayout(...)
Return p
End Sub
Add the returned panel to your layout.
A more robust approach is to create a class for this panel. This will make it easier to handle the events of the controls inside the panel.