I need to override the given default Auto return URL from the paypal button HTML code. I followed these steps:
- Check the Auto return Url section and gave a default URL
- Generate a Buy Nowbutton and left theReturnandCancelURL options as it is.
- Paste the button code - <form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post" target="_top"> <input type="hidden" name="return" value="http://www.someURL.com"/> <input type="hidden" name="cmd" value="_s-xclick"> <input type="hidden" name="hosted_button_id" value="G3WQ*******"> <input type="image" src="https://www.sandbox.paypal.com/en_GB/i/btn/btn_buynowCC_LG.gif" border="0" name="submit" alt="PayPal – The safer, easier way to pay online!"> <img alt="" border="0" src="https://www.sandbox.paypal.com/en_GB/i/scr/pixel.gif" width="1" height="1"> </form>
After successful payment on Sandbox PayPal is always redirecting me to the default URL. 
Why isn't overriding it? Any help would be appreciable.
I saw a couple of similar unanswered question on PayPal community and StackOverflow as well:
 
    