Example 4: The Root Object
This sets the object that will be returned from a call to SE_GetRootObject().
The Root Object must be a Transmittal Root Object.
If the root object was set previously, then the old root object is returned in old_root_object.
NULL may be passed in for old_root_object.
SE_Return_Code SE_SetRootObject
SE_Transmittal transmittal,
SE_Object new_root_object,
SE_Object *old_root_object