rem: KNHeaders::From* from(bool create=true)           { if(!create && f_rom.isEmpty()) return 0; return &f_rom; }
add: virtual KNHeaders::From* from(bool create=true)                  { KNHeaders::From *p=0; return getHeaderInstance(p, create); }
context:     KNHeaders::From* from(bool create=true)           { if(!create && f_rom.isEmpty()) return 0; return &f_rom; }