playing maps through mods?[Beta 1.1]

so, i for some reason just found out i can make maps come out on the Mods list in the game options. i just make a folder and and the the map files in folders inside a folder to make em work... its hard to explain. Here's an example of what i mean:

[Sorry if this is hard to understand, but this is what i mean]
----------------------------------------------->data———————>(map Data)
-------------|>  (map folder)———————>maps———————> (map's .bsp file)
-------------|
-------------|--------—|>data
-------------|--------—|>env
PC Version>—>nzp—|>GFX
-------------|--------—|>maps
-------------|--------—|>progs
-------------|--------—|>etc...
-------------|> Nazi Zombies Portable.exe


so if you under stood this, thats good(de ja vu...).
the only problem i'm having with this is that there are no sound when i try playing the map through the mods list. can someone tell me the reason for this? i need a solution so i can improve Beta 1.1 Maps. please and thank you for your time.