Redbox not working with forms - alternative?

Question

I've installed Redbox, a lightbox solution for rails. It works fine, but I'm trying to use it for a form. Part of the form is in my view, but part of the form and the submit button are in the box:

            <div id="confirm", style="display:none;">
                Are you sure you want to go?<br><br>

                <%= f.check_box :accept_toc %> I accept the <%=link_to "Terms and Conditions", {:controller => "general", :action => "terms"}, :onclick => 'RedBox.close()' %>
                <br />

                <%=link_to_close_redbox "Go back" %>
                <%= f.submit "Register", :onclick => 'RedBox.close()' %>

            </div>

f.submit closes the redbox, but doesn't do anything else. Is there a solution or alternative thickbox built for rails? I know development for redbox stopped a while ago.