No sound at XBMC autostart

Hello everyone,,

I joined the XBMC world recently. I have a Zotac AQ01 increased with 4GB Ram and SSD disk.
I installed an Ubuntu 13.10 - ATI driver works very well, (have no stuttering, etc.)

Because everything worked so wonderful, I thought, now I put everything else so the XBMC starts right away.
Have some solutions found how to do that best.
I decided then for the following solution:

adjust the /etc/lightdm/lightdm.conf

[SeatDefaults]
autologin-user = xbmc autologin
-user-timeout = 0
user-session = XBMC
greeter-session = lightdm-gtk-greeter

Creating the /usr/share/xsessions/XBMC.desktop

[Desktop Entry]
Name = XBMC
Comment = This session will start XBMC Media Center
Exec = xbmc-standalonereverse phone lookupnba reddit pcpartpicker

TryExec = xbmc-standalone
Type = Application

The autostart works very well. Only now I have the problem that I rausbringe no sound over HDMI more.

The problem is as follows:
I [definition='1','0']log[/definition] in with the user xbm in the Unity interface and start xbmc the sound works fine.
If I do not [definition='1','0']log[/definition] in to the Unity interface, I choose XBMC right away when [definition=12,9]logging[/definition] in, or I do not have an HDMI sound on the autostart.
When I start XBMC in Unity I also have additional audio output devices (HDMI # 0, HDMI # 1) I do not have these in the autostart.

Have already tried the search function. There are many topics about "no sound via HDMI", I have already tried one or the other but unfortunately without success.

Does anyone have an idea about this?

Many thanks for your help