Enable/disable text entry in IntCtrl on RadioButton click in wxPython

I have a simple gui that has two radio buttons and an IntCtrl for text entry. Initially, I have the top radio button selected and the IntCtrl disabled (unfortunately, I can't figure out how to set it to blank or "grayed out"):

Relevant code snippet:

def loadSettingsPanel(self):
    panel = wx.Panel(self)

    self.exposureAutomatic = wx.RadioButton(panel, label="Automatic (1ms)", style=wx.RB_GROUP)
    self.exposureManual = wx.RadioButton(panel, label="Manual")
    self.exposureValue = wx.lib.intctrl.IntCtrl(panel, style=wx.TE_READONLY)

    self.exposureManual.Bind(wx.EVT_RADIOBUTTON, self.onClick)

    # Add sizers, etc.

I want to "enable" the IntCtrl area in the onClick method, but I can't figure out how to do this. SetStyle() doesn't seem to have the option clear out the wx.TE_READONLY styling and I'd prefer not to recreate the IntCtrl entirely because then it gets annoying to reshuffle everything in the sizer. If there's some way to do this using a TextCtrl, I'd be happy to switch to that and just do the character filtering manually, but I haven't been able to figure out how to enable/disable those either.

Use the Enable function rather than a style.

import wx
import wx.lib.intctrl

class MyFrame(wx.Frame):

    def __init__(self, parent):

        wx.Frame.__init__(self, parent, -1, "Intctrl Demo")

        panel = wx.Panel(self)
        self.exposureAutomatic = wx.RadioButton(panel, label="Automatic (1ms)", style=wx.RB_GROUP, pos=(50,50))
        self.exposureManual = wx.RadioButton(panel, label="Manual", pos=(50,80))
        self.ic = wx.lib.intctrl.IntCtrl(panel, -1, pos=(150, 80))
        self.ic.Enable(False)
        self.Bind(wx.EVT_RADIOBUTTON, self.onClick)

    def onClick(self, event):
        self.ic.Enable(self.exposureManual.GetValue())


app = wx.App()

frame = MyFrame(None)
app.SetTopWindow(frame)
frame.Show()

app.MainLoop()