WScript.Timeout = 120
Set objRequest = CreateObject("Msxml2.ServerXMLHTTP")
URL = "http://localhost:8080/xbmcCmds/xbmcHttp?command=ExecBuiltIn¶meter=XBMC.updatelibrary(video)"
objRequest.open "GET", URL , false, "username", "password"
Set objRequest = Nothing
I set up the web interface so that it runs on port 8080 with my desired username and password, used the Msxml2.ServerXMLHTTP object to make the HTTP request and voilà! It works.
I added a scheduled task in order to make it update frequently. I guess you could modify the application so that it recognizes changes amongst the files but one update an hour works fine for me.