Exactly what I was looking for. Thanks, Tihiy!
Could I twist your arm into rescanning the "Right side items" folders when doing a refresh? I'm still experiencing the problem I reported here whereby, because my network drive isn't immediately available at login, SIB doesn't display items like my Downloads folder located on that drive. I've been using a batch file at login to forcibly map the drive as quickly as possible and then restart explorer.exe (SIB rescans when you restart explorer.exe), but sometimes this occurs so quickly that not all my startup items load before explorer.exe is terminated, leaving me to try and figure out what didn't load and start it manually. If I could refresh SIB with SendMessage after the drive map completes instead of restarting explorer.exe, I'd finally have an acceptable workaround for this issue.