usually you get a error message saying something about a configuration error and that you must contact the service provider. so not a recommended thing to do. especially if the regions of your CDA and your FS dont match. but hey!...if it works then good for you.
edit: are you actually asking if you can do it? or is it that you have done it and that your asking if there is anything bad about it?
...like i said it normally gives you and error but if you already have done it and it works then just use it, there might be just a few positions of stuff swoped around.