We have audio files with additional information in an extended header.
When I edit a MuLaw (.au) file, the data offset is not honored.

#ifndef __AU_Header_h__
#define __AU_Header_h__

typedef struct
{
    unsigned long    magic_number;     // .snd
    unsigned long    data_offset;          // offset to data 
    unsigned long    data_size;            // number of data objects
    unsigned long    encoding;             // scheme 1 = 8 bit mulaw, 3 = 16 bit linear
    unsigned long    sample_rate;        // sample rate 8khz
    unsigned long    num_channels;     // number of channels

} AU_Header;

#endif // __AU_Header_h__

I there any way for the software to honor the header like the very old Cool Edit 2000 does?