Color Key Masking Issue (Persits PDF)

Color Key Masking Issue (Persits PDF)

I read this manual, http://www.asppdf.com/manual_05.html#5_2_2, but this
can't work with CMYK image!
I tryed declare 4 parameters and setting this values, but nothing...
Set Image = Doc.OpenImage(Server.MapPath(x))
Image.SetColorMask "Min1=1;Max1=7; Min2=80;Max2=89; Min3=0;Max3=5;
Min4=0;Max4=5"