We updated the XML for the Custom Event Viewer filter to include failed logon attempts via RDP.
You can find the XML code along with instructions for creating the custom filter in the Event Viewer here: SBS CodePlex Custom Event Viewer Filter for Failed Logons.
Note that there are other XML files for Event Viewer custom filters along with the XML code to flag the failed logons in the SBS Console among other server events.
Microsoft Small Business Specialists
Co-Author: SBS 2008 Blueprint Book
*All Mac on SBS posts will not be written on a Mac until we replace our now missing iMac!