If you are NOT using SSL at your site you may get the "there are secure and non-secure items" warning from worldpay as the callback is made. This is because the standard wpcallback.php page uses your standard site images (which are not secure!).

I have removed all images and the warning message is no more!

This is a new wpcallback.php file ONLY with all images and reference to the main stylesheet removed.

It works for me but backup first and test after!

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