Volume control unit with tivo remote?

I'm looking to use my music amp with my TV and bookshelf speakers. The amp doesn't have any IR volume control.



My TV only has optical line out and I'd like to control the volume with my Tivo remote.



So I'm looking for a box that will take a digital line in from my tv, output analog audio, and has a volume control that can be controlled with my tivo remote.



Does anyone know of such a device?



Thanks.