Anyone know if it is possible to add territory to map using map point control in C# application? (Something like in normal MapPoint 2010 application) If so, how I can use it?
It looks like you need to use the Datasets collection's LinkTerritories() method.
The "dataset loading" methods (eg. to create pie charts and shaded area maps) are a bit of a hairy area in MapPoint's API. With their many parameters they are easy to get wrong and the resulting error message is less than useful - typically just "bad parameter". So be warned!