I'm writing a program for all that stuff.. but the way i do it is by using a dirty C program i wrote to dump all the images in the bin into BCLIMs and use Ohana3DS to edit them lol..
there's only sound effects in there.. they are in the form of CWAV.. what i did was go to the address pointed to by 0xBC and made a new CWAV and copied it right over the old one such that the magics match up and everything (because theres some wierd in between that address and the CWAV magic.. ) so after you copy in your new one, move 0xC bytes in to the CWAV to find your length, and just copy that into the weird header at the length offset (i dont recall what the offset is off hand but you cant miss it.. its near the end.)