Redirect Registered Customer issue

[robertdrag]

Hi,
I add this condition on the Proceed to Checkout button:

<?php if ($this->isPossibleOnepageCheckout() && Mage::getSingleton('customer/session')->isLoggedIn()):?>
    <button type="button" title="<?php echo Mage::helper('core')->quoteEscape($this->__('Proceed to Checkout')) ?>" class="button btn-proceed-checkout btn-checkout<?php if ($this->isDisabled()):?> no-checkout<?php endif; ?>"<?php if ($this->isDisabled()):?> disabled="disabled"<?php endif; ?> onclick="window.location='<?php echo $this->getCheckoutUrl() ?>';"><span><span><?php echo $this->__('Proceed to Checkout') ?></span></span></button>
<?php else: ?>
    <button type="button" title="<?php echo Mage::helper('core')->quoteEscape($this->__('Proceed to Checkout')) ?>" class="button btn-proceed-checkout btn-checkout<?php if ($this->isDisabled()):?> no-checkout<?php endif; ?>"<?php if ($this->isDisabled()):?> disabled="disabled"<?php endif; ?> onclick="window.location='<?php echo Mage::getUrl('customer/account/login'); ?>';"><span><span><?php echo $this->__('Proceed to Checkout') ?></span></span></button>
<?php endif?>

So when a user is not login on my store will be redirected to Login / Register page. I made a custom function to redirect the customers after register to checkout page if the was in Shopping Cart else redirect to My Account. But I don't know what is wrong, because now after register I am redirect only to My Account. So I want to redirect customer after registration to the Checkout page if the customer was in the Shopping Cart else to My Account. This is my function:

   public function customerRegistration(Varien_Event_Observer $observer)
   {
      if(Mage::getSingleton('core/session')->getIsFromCart() == 1 || Mage::getSingleton('core/session')->getIsFromCheckout() == 1){
            Mage::app()->getFrontController()->getResponse()->setRedirect(Mage::getUrl('onestepcheckout/index'));
            Mage::app()->getResponse()->sendResponse();
            exit;
         }
    else
        {
            Mage::app()->getFrontController()->getResponse()->setRedirect(Mage::getUrl('customer/account'));
            Mage::app()->getResponse()->sendResponse();
            exit;
        }
         Mage::getSingleton('core/session')->setIsFromCart('0');
    Mage::getSingleton('core/session')->setIsFromCheckout('0');
   }

and this is my observer in the config.xml

    <customer_register_success>
        <observers>
          <customerredirect>
            <class>customerredirect/observer_customer</class>
            <method>customerRegistration</method>
          </customerredirect>
        </observers>
    </customer_register_success>

Thank you very much

Update:

Someone told me that is a way to do this. To add an event before going to register page, add an event observer after registration is complete and then check what is necessary. But I don't know to do this, maybe someone can help me with this?

New Update:

I found what is the problem: I check if the Last url was shopping cart and then I add some condition, for login when I check the last url is the shopping cart, but in register.phtml when I check if the LastUrl is Shopping cart is false, because there the LastUrl is login, how I can make this check to work on the register.phtml? In fact I need to check back for third Url.
Thank you

[senthilms]

Login to Magento Admin --> System --> Configuration --> Sales -->Checkout -->Allow Guest Checkout --> Set to "No"

And you can revert all the above changes. Because Magento will redirect the user to login or register. 

[robertdrag]

Hi,

thank you for your answer but I want to tell you  Login to Magento Admin --> System --> Configuration --> Sales -->Checkout -->Allow Guest Checkout --> is Set to "No" already in my store, but my checkout page is not a default Magento. My checkout page need authentication in the checkout one page and I need to remove that authentication. For that I add that condition in the link.phtml on the Proceed to Checkout button, for that I need this code to work. Will be very fine if you can tell me a solution. Thank you.