CreateUserWizard - Access Text Box .Text

I have a CreateUserWizard with an added step "CompanyInfo".
<WizardSteps>
            <asp:WizardStep ID="CompanyInfo" runat="server">
            <asp:TextBox ID="CompanyName" ... ></asp:TextBox>
...
            </asp:WizardStep>
            <asp:CreateUserWizardStep>
...
           </asp:CreateUserWizardStep>
<WizardSteps>
From the CreatedUser handler, I want to access the content of the CompanyName textbox. 
I've tried various means to get to this this textbox, most recently:
          TextBox t = (TextBox) CreateUserWizard1. ...