Page redirect after submission

Greetings! First of all, great job on forking the plugin and supporting it.

I wonder about one thing that has not been discussed before on this plugin.
I tried several different solutions to redirect to a sort of a Thank You page after successful submission of the form, but I was not successful.

Would you be able to point me in the right direction? I see that the form is not in a typical format so this is why the redirects might not be working. I tried adding a different header after submit, including an external redirect script but it did not work.

Any help would be greatly appreciated!

Branislav