Can't get Cucumber/Capybara to find radio buttons - ruby-on-rails-3

Question

I'm having trouble getting Cucumber to "choose" a radio button and hoping someone can give me a sanity check. Without quoting a huge mass of HTML junk, here's the relevant portion (which I collected from print.html). It's within a modal div that is activated by a button. I can "click" that button and see the modal window appear (I'm running it as a #javascript scenario in Selenium).
<div class="modal-body pagination-centered">
<img src="/assets/payment.png" alt="Payment" />
<form novalidate="novalidate" method="post" id="edit_cart_1" class="simple_form edit_cart" action="/carts/complete" accept-charset="UTF-8">
<div style="margin:0;padding:0;display:inline">
<input type="hidden" value="✓" name="utf8" />
<input type="hidden" value="put" name="_method" />
</div>
<div class="control-group hidden cart_property_id">
<div class="controls">
<input type="hidden" name="cart[property_id]" id="cart_property_id" class="hidden" />
</div>
</div>
<div id="payment_fat_buttons" class="fat-buttons">
<div class="vertical-button-wrapper">
<input type="radio" value="cash" name="cart[payment_type]" id="cart_payment_type_cash_pay" data-property-id="1" />
<label for="cart_payment_type_cash_pay">Cash</label>
</div>
<div class="vertical-button-wrapper">
<input type="radio" value="credit" name="cart[payment_type]" id="cart_payment_type_credit_pay" data-property-id="1" />
<label for="cart_payment_type_credit_pay">Credit</label>
</div>
</div>
<div style="display: none;" id="cart_room_number_area_pay">
<div class="control-group string optional cart_room_number">
<label for="cart_room_number_pay" class="string optional control-label">Room number</label>
<div class="controls">
<input type="text" value="" size="50" name="cart[room_number]" id="cart_room_number_pay" class="string optional" />
</div>
</div>
</div>
<input type="checkbox" value="1" style="display: none;" name="receipt" id="receipt" />
<div class="sell-modal-footer">
<input type="submit" value="Complete With Receipt" name="commit" id="cart_complete_with_receipt" data_disable_with="Processing..." class="btn btn-danger" />
<input type="submit" value="Complete Sale" name="commit" data_disable_with="Processing..." class="btn btn-danger" />
</div>
</form>
</div>
I've tried as many different equivalent ways of getting at it that I can think of. Most obviously just by the label, or the ID, like:
choose 'cart_payment_type_cash_pay'
choose 'Cash'
which just gives me the error:
Unable to find radio button "cart_payment_type_cash_pay" (Capybara::ElementNotFound)
I thought it might have something to do with the modal dialog, visibility, etc. but I introduced the ID #payment_fat_buttons just for testing, and when I look for it like this:
find('#payment_fat_buttons').choose('Cash')
it finds that DIV OK, but still not the radio button. I also tried getting at it with :xpath on the whole page, and within a scope like:
within(:xpath, "//div[#id='payment_methods']") do
find(:xpath, ".//input[#id='cart_payment_type_cash_pay']").choose
end
which acts like it can also find the outer DIV, but not the radio button - I get the error:
Unable to find xpath ".//input[#id='cart_payment_type_cash_pay']" (Capybara::ElementNotFound)
Generally, it seems like I can find any arbitrary element around the radio buttons with :xpath or CSS expressions, just not the radio buttons. I can also push the submit buttons on the form without any problem. I tried dropping the data attributes as a test - no difference. Any help would be greatly appreciated. This is driving me nuts because it seems so simple, and yet I'm getting nowhere. I need to choose that for a big segment of Scenarios, so if I can't figure it out, I'll have to resort to something hokey and horrible. Many thanks in advance...
Relevant versions from Gemfile.lock:
rails (3.2.13)
cucumber (1.3.8)
gherkin (2.12.2)
cucumber-rails (1.4.0)
capybara (2.1.0)
selenium-webdriver (2.35.1)

Answer 1

I finally figured this one out. Capybara wasn't finding the radio button because buried deep in my styles was some CSS that hid it in order to change the appearance. Once I realized that, I figured out that I could side-step the whole issue of finding the radio button by just doing a click on the label instead:
find(:xpath, "//label[#for='the_radio_button_id']").click
I didn't realize it was possible to get at radio buttons that way - but in any case, it solves the issue of how to click a radio button that Capybara won't find due to styling or other issues. Hope that helps someone else.