I have created a new task based on your settings. The only special thing I saw with your settings is that you use SFTP. SFTP and FTP are 2 totally different protocols, even if they share the "ftp" in their name, they work totally different.
Created the task, let it do an initial scan (so all current file sizes and timestamps are recorded without taking action), used FileZilla again to download/re-upload a file so its timestamps are touched.
The file was detected by WF and my bat file triggered. What you can try, on the FTP Server Settings tab, is check the option "keep session log". This will record all activity in a yyyymmdd.log file (or right-click the task and "view session log"). Run the task and (after touching existingfile.txt) open the log. Search for all occurrences of existingfile.txt and you should some filesize/timestamp info for the file.
For example, I "touched" the file "dfsgsddfz- kopie.txt", and see the following in the log:
20140202 064253 ** found file dfsgsddfz- kopie.txt
20140202 064253 Size 5005
20140202 064253 Last Modif 30-8-2012 11:47:08
20140202 064253 Created 30-8-2012 11:47:08
...
20140202 064723 ** found file dfsgsddfz- kopie.txt
20140202 064723 Size 5005
20140202 064723 Last Modif 2-2-2014 6:46:57
20140202 064723 Created 2-2-2014 6:46:57
and my bat file triggered fine. I now see the logging code doesn't log the fact it will trigger actions in this case, I will add that to the code.
My bat script is really simple, it just echos all environment variables:
Code:SET WF_ > f:\testing\output.log
and after running the task, this is what I see in my output.log file
Code:WF_AGECREATED_DAYS=
WF_AGECREATED_HOURS=
WF_AGEMODIFIED_DAYS=
WF_AGEMODIFIED_HOURS=
WF_CONFIG=RCTEST
WF_CUREVT=1391320042
WF_CURRUN=1
WF_DATE=20140202
WF_DIR=
WF_DTTM=20140202 064752
WF_FILE=C:\TaskDoesntDownload\home\watchdir\WATCHFTPTESTS\dfsgsddfz- kopie.txt
WF_FILE_B=dfsgsddfz- kopie
WF_FILE_D=C:\TaskDoesntDownload\home\watchdir\WATCHFTPTESTS\
WF_FILE_DATE_CR=
WF_FILE_DATE_LM=
WF_FILE_E=TXT
WF_FILE_LOCAL=C:\TaskDoesntDownload\home\watchdir\WATCHFTPTESTS\dfsgsddfz- kopie.txt
WF_FILE_N=dfsgsddfz- kopie.txt
WF_FILE_REMOTE=/home/watchdir/WATCHFTPTESTS/dfsgsddfz- kopie.txt
WF_FILE_SHORTNAME=
WF_FILE_SHORTPATH=
WF_FILE_SIZE=
WF_FILE_SIZE_KB=
WF_FILE_TIME_CR=
WF_FILE_TIME_LM=
WF_FIRSTDIR=:
WF_INSTDIR=C:\Program Files\WatchFTP
WF_OFILE=
WF_OFILE_B=
WF_OFILE_D=
WF_OFILE_E=
WF_OFILE_N=
WF_ORELDIR=
WF_PARENTDIR=WATCHFTPTESTS
WF_REASON=FILENEW
WF_RELDIR=:\TaskDoesntDownload\home\watchdir\WATCHFTPTESTS
WF_TASK=RCTEST
WF_TASKDIR=C:\ProgramData\WatchFTP\RCTEST
WF_TIME=064752
Note that I asked you for a task backup earlier so I could properly look at your settings and recreate the task. Sorry to hear you don't appreciate 7-days per week service from the one person in my company that knows most about the working of our programs.