I have to agree with Guitarist on this one. I spent three years "trying" to let go of the tension by conciously relaxing my fingers. It would take all my will power and was exhausting to the point of making me light headed. Eventually I would get to the point where I could play very slowly without the dystonia but as soon as I stopped concentrating or tried to play "normally it would be back in no time.I went to see Prof Fabfra in Madrid in May this year and he totally opened my eyes to a different approach. His definition of not fighting the dystonia is just that - let it happen. Right at the beginning we have to lose our fear of it and allow the fingers to do whatever they like. But - and this is a vital point - we must be very careful to not react emotionally in any way to the fact our movements feel strange. Joaquin's theory is that the dystonia feeds off negative emotion such as fear. If you just let the fingers do what they want but still allow yourself to be swamped by that same feeling of hopelessness/fear/anguish/frustration/annoyance you will reinforce the dystonic movement. This is the danger when trying to convey a subtle method using a few phrases. I only really understood this properly when sitting in front of Joaquin for 5 solid days.
During this time I never tried to control the dystonic movements - they were allowed to happen. I was asked to play normally as if I didn't have FD. Simultaneous to this I trained my mind to remain emotionally passive to the results of the commands my brain was sending to the fingers (easier said than done). By the third day my hand/fingers were significantly improved from what they had been for three years before that point. Things have continued to improve since using this approach so it obviously works for me. However everyone is different so I'm very wary of saying "this is what you should do". If you do try the approach I would suggest doing it in isolation from whatever other methods you use for three days only. Then assess the situation objectively and if there is little or no improvement you are either doing it wrong (STOP!) or it is not compatible with your particular condition.
Note: I am still preparing a detailed report/anaysis of my visit to Madrid but I keep editing it as I'm very wary of conveying the wrong message and sending some people "up the garden path".