cygwin - rdiff-backup on WindowsOS: cannot get "--exclude C:/target/stuff" to work -

i working on backing number of local , non-local files windows machine. familiar rdiff-backup other linux boxes use. have installed rdiff-backup using instructions etc here, http://www.nongnu.org/rdiff-backup/index.html

i have rdiff-backup installed , appears working "almost" fine. problem have directory want exclude. on linux os do,

rdiff-backup --exclude c:/target/stuff c:/ d:/backup  

however not work on windowsos machine. using suggested formatting posted here:

http://www.nongnu.org/rdiff-backup/windows-readme.txt

i have tried following,

rdiff-backup --exclude "c:/target/stuff" c:/ d:/backup  

also escape characters...

rdiff-backup --exclude c:\\/target\\/stuff c:/ d:/backup 

as doing "c:/" directory,

with no luck @ all.