Yes, contacting Rebus directly would be the best solution. They are very responsive and provide great, easy to understand answers.
I have just contacted them and was informed that for now denoising is disabled due to some technical difficulties - it is probably better to end up with good looking non-denoised image, than with one which is denoised, but has some artifacts like seams, and cannot be used anywhere. I am sure that this will be soon sorted between our team and Rebus, and you will be able to use the CXR format and denoising without any troubles.