For anyone who cares or can use the info....
I just futtzed around with this (if I may use "futtz" in a sentence, thanks) and got it to work. The clearly missing piece came from the iSiloXC manual, posted below. I will admit to being a slacker and not reading the manual until something doesn't work right. Now it's just a matter of figuring out what a good schedule for me to do this is If there's a better scheduling program out there for Windows, I'd love to know about it!
If you use a scheduler to schedule iSiloXC, you may want to have iSiloXC update the last conversion status. Under Windows, you might provide to the Windows scheduler a command line similar to the following:
"C:\Program Files\iSilo\iSiloX\iSiloXC.exe" -x "C:\My Documents\iSilo\
WWW.ixl" -u
The double quotes around the path to the executable and the path to the conversion list file are necessary because both paths have spaces.