Dtsplus missing inlcude FIle

Hi, i wanna compile the dtsPlus exporter for max, but on a clean Project Build its missing dtsdecimator.h
i searched for the File, but without result.

i need it to change the Exporter, wanna try to implement something like this:
www.garagegames.com/index.php?sec=mg&mod=resource&page=view&qid=11278
in the dtsplus exporter.

thx
-Miguel