Congratulations on your first post. We look forward to hearing more from you.
To my knowledge, S&T maps are not user-extensible, and this is true of Mappoint as well. Delorme Street Atlas does allow you to "draw routable roads" (with limitations).
Your best shot is to contribute to the master database. The bulk of US map data in S&T is supplied by Navteq, so you can check Navteq Mapreporter (
Redirecting to the NAVTEQ Map Reporter homepage). If this is also incorrect, then you can report corrections. Turnaround time will depend on your location. In central Jersey, I get about 3-month turnaround on my road and address reports, and my POI reports have all been totally ignored.
If the Mapreporter data is correct, then it should make it into the next version of S&T (or the one after that). The lag is 9-21 months depending on whether you make the cutoff. For example, S&T 2009 was released in August 2008, and the data is current as of Q4 2007. So anything that just barely missed the Q4 deadline will not appear until S&T 2010 is released sometime this summer or fall.