I've tried Mirror Box Therapy with my Physiotherapist's for severe Dystonia in my left leg. My foot is rotated out to the side and has been for 3 and a half years.
I'm sad to say that the mirror therapy didn't work for me. I had physio 3 times weekly and also was allowed to take the mirror box home with me to try. I tried it for about 3 months then my doctor and physio decided my Dystonia was too advanced so i'd need medications to try and correct it ... sadly none of those worked either and I am now looking into having a Baclofen pump inserted in my spine although my doctor won't do this yet as i'm only 16.
As i'm sure you know, what works for one person with RSD won't work for the other. I'd definitely give it a shot though! It DOES hurt (as do most things with RSD) but you do get used to it a little and if it works it'd be totally worth it !
Good Luck! I hope you have positive results and please keep us posted!