Hi,
Normally, there is a thank you message on that "blank page".
If you don't see it, it's possible that your template is not displaying the messages:
www.hikashop.com/support/support/documen...tibility-issues.html
I just checked but there is not yet the option for the URL redirection in the PayPal Express plugin.
Add the line:
'return_url' => array('RETURN_URL', 'input'),
after the line:
'sandbox' => array('SANDBOX', 'boolean','0'),
in the file plugins/hikashoppayment/paypalexpress.php and that will add an option to your payment method called "return URL" where you can configure it.