Disklavier

Purchased the DKC-850  and installing it myself.  
The Grand Touch (Digital Piano)   DGT7A with the   DKC-55RCD  

Problems:  

1. There is no include mounting bracket and the 55RCD's bracket is too narrow. Where do I  get one that fit the 850?

2. I cannot find how to get the Piano and a voice to play at the same time?  Voice is via the MIDI AUX inputs  using  the RCA  to Head phone cables.

3. The Metronome only plays out the 850's rear speaker, and very quiet..

4.When on Piano only , the sound quality does not seem as nice as the original with the DKC-55RCD

5. There is no "CD CONTROL UNIT"  plug on the back of the 850 like on the 55RCD thus a cbale goes unplugged..


Any help appreciated...