OK, I'm attaching the batch file, some mod please validate it. Just create a shortcut to it on your desktop and then drag and drop the .SON file to be converted onto the shortcut. It will create the .SST file in the same directory as the .SON file.
Now as for how to get the .SON file... I'm not using DIF4U but I suppose it creates .SUB and .IDX files somewhere using VsRip. You need to use VsConv.exe (in your DIF4U directory) to extract subs from the .idx file in Maestro format. It's command line, just run it to get available options. For example
Code:
vsconv -f "maestro" -i "d:\somedir\somesubs.idx" -o "d:\someotherdir\subs.son" -id 0 -forcedonly