How do I specify particular points for discretization in Pyomo?

I have a continuous-time Pyomo model of the form:

from pyomo.environ import *
from pyomo.dae import *

m      = ConcreteModel()
m.t    = ContinuousSet(bounds=(0,150)) 
m.T    = Param(default=150)
m.S    = Var(m.t, bounds=(0,None))
m.Sdot = DerivativeVar(m.S)

discretizer = TransformationFactory('dae.collocation')
discretizer.apply_to(m,nfe=100,ncp=3,scheme='LAGRANGE-RADAU')

m.obj  = Objective(expr=m.S[122],sense=maximize)

But, when I run the above code, I get the following error:

KeyError: "Error accessing indexed component: Index '120' is not valid for array component 'S'"

Looking at list(m.t), I see that, sure enough, 122 is not included as a discretization point:

..., 121.73257700000001, 122.467423, ...

How can I specify points to be included in the discretization?