Thanks for writing in!
Slider Revolution can be used in Pro theme. If you are referring to the Slider Settings: Below/Above Masthead settings, then most probably the slider no longer displays because you have assigned a custom header. Please understand that the slider settings is part of the default header. As soon as you create and assign a custom header, the slider will be replaced along with the default header with the new custom header. If you want to display a slider in your custom header, you will need to create a bar and insert a text element. You can then make sue of the slider shortcode and be able to display the slider within your custom header.
Hope this makes sense.