Actually, you DO need to use special ZENworks macros. Using cmd.exe as the command, the following command line does NOT produce a log:

zac statussender RollUp syn > %Temp%\zcminvlog.txt

However, the following will produce a log:

statussender RollUp syn > ${TempDir}\zcminvlog.txt

BTW, it is a single > for overwriting the file and two >> to append to the file.

After rewriting the bundle to do the above, I still get the situation where the inventory doesn't get pushed up on the zac refresh command that is run in the bundle. It will get pushed up if you issue the command manually. I even added a 30 second delay in the bundle before the refresh and it still didn't work.