In Creation Kit.
00 Skyrim.esm
01 Update.esm
02 YourMod.esp <--Custom music will be hexcoded 02, making them be referenced to this loadorder
In Skyrim
00 Skyrim.esm
01 Update.esm
02 YourMod.esp <-Custom music will be searched for here at 02, and found, thus you avoid the CTD.
If you want other plugins loaded before it, (mainly esm's as you can't load esp's above them), then you should create dummy esp's which are loaded before the plugin in the CK. they need to be esp's as then they won't be saved as necessary masters in the plugin file header, but the load order will still be saved.
in Creation Kit.
00 Skyrim.esm
01 Update.esm
02 Dummy.esp
03 YourMod.esp <--- Saved as 03
In Skyrim
00 Skyrim.esm
01 Update.esm
02 Another esm.esm
03 YourMod.esp < - loaded in the 03 position

