I did some full research on the eXdupe pre-process file. It looks like that was difficult to make it both stdin and stdout. So I did this to make it work by using the latest version of eXdupe like this:
Code:
[External compressor:exdupe]
header = 0
packcmd = exdupe -x0 -g1 -t2 $$arcdatafile$$.tmp -stdout <stdout>
unpackcmd = exdupe -R $$arcpackedfile$$.tmp -stdout <stdout>
Hope you guys can try if it works or not.