We us this technique every day. Our SSIS jobs will trigger the appropriate extract refreshes on our server once the corresponding data mart has been loaded.
In our first iteration I created 3 simple packages that could be used.
1. A package to login into a particular Site
2. A package to log out of the Site
3. A package to refresh a particular extract which also calls package 1 & 2
Hope this helps. Feel free to reach out to me and I could discuss it further.