Default SlimKat : Use mirroring with chromecast

Hi all,

I have a Galaxy Nexus with SlimKat 4.4 build 6.6. I try to use mirroring with chromecast but it doesn't works because the device is not compatible.
But it's possible to enable for all devices with this application :
It works with Galaxy Nexus but they said :

For those STILL having issues,
Check /system/lib/hw directory for the file "".
If it doesn't exist, ask your device maintainer to add audio.r_submix.default to
the product_packages in the file. (You may not know what it means, but they will.)
Is any way to add this feature ?
I have not permission to post in the ROM discussion because i'm new . Maybe someone can help me to add this feature in the ROM ?

Thanks you !