spdif volume control in vista

Hi, I have built myself a htpc have ironed out most problems now but am still facing a niggly issue regarding control over the volume when playing ac3 and outputting spdif i would really like a way to control the volume level which i can then map to a remote as using the volume control on my amp is a pain as its in a cabinet and a really dont want to have to have the cabinet door open, i use ffdshow audio decoder to process the sound and i am able to use the ffdshow settings to change the volume but have found no way of taking control over this setting so that i can alter it without actually going into the ffdshow menu so i am hoping someone may know a way to do this or any other program that i could use to do the same thing, i know there is a program called master fader which i believe enables you to do this in xp but does not work on vista, have spent hours googling this issue with no luck any help would be much apreciated.
Thanks, James.

So the amp you are using has no remote? If it does and it is merely the cabinet door that is causing the issue, then the simple way would be to use a remote extender (or make one yourself). Alternatively get a window cut into the cabinet... or change the cabinet door for a glass one.

SPDIF is a digital output so what you are asking to do is lower or raise the output level of the SPDIF from the computer. This means that your recordings might well be all over the place.... read more here

thanks for you sugestions NooNoo however its not possible to put a glass door on this cabinet or cut a whole in it, the extender is kinda an option but it might sound picky but i would really like to just use the one remote and my existing media center remote has no learning feature as it is obviously possible for the volume to be controlled from the operating system as ffdshow does do it i am amazed if there is no other software that will do this seems like there is a lot of people wanting to do the same as me, if not i will just have to live with getting up and manually changing the volume on the amp, will keep checking this post incase anyone ever finds a solution, thanks for your help.

Sorry, but really you are trying to solve the wrong problem here. Buy an extender and a learning remote... much better than discovering that someone turned down the sound while recording your favourite show so that you can't hear it!