Thanks fior the reply.
Does unmodelled mean there is no com object that can be used behind the scene?
I've never touch extensibility before.

All I'm doing is writting an add for VS2003.

Not sure what IVsHierarchy, is that a VS2005 feature?I'm using VS2003

Here's the code I ended up with to add a sql file to the database project of
the solution.

Ideally I would haver like to test if the a given folder existed, create it
if not and then and add the new file in that folder.

string fileName = System.Environment.GetEnvironmentVariable("TMP") + "\\" +
storedProcName + ".sql";
                           
//Save the code to file
if(SaveCodeToFile(fileName,SQLComand)){
    //Should hopefully give us the name of the solution
    string slnName =
System.IO.Path.GetFileNameWithoutExtension(applicationObject.Solution.FullName);
    string item = slnName + "\\" + dbProjectName; // + "\\Queries";    //location
where the new file is to be added
                                   
    //Handle on Solution Explorer window
    EnvDTE.Window slnExplorer =
applicationObject.Windows.Item(Constants.vsWindowKindSolutionExplorer);
                        slnExplorer.Activate();

    //get the Database project so we can add a folder to it.
                        //EnvDTE.UIHierarchyItem dbProj =
((EnvDTE.UIHierarchy)applicationObject.Application.ActiveWindow.Object).GetItem(item);
    //dbProj.Select(vsUISelectionType.vsUISelectionTypeSelect);
                                //Select the folder into which we want to add the new stored
procedure.
                        EnvDTE.UIHierarchyItem X = ((EnvDTE.UIHierarchy)
applicationObject.Application.ActiveWindow.Object).GetItem(item);
    X.Select(vsUISelectionType.vsUISelectionTypeSelect);

    EnvDTE.Window newStoredProc =
(EnvDTE.Window)applicationObject.ItemOperations.AddExistingItem(fileName);
    X.Select(vsUISelectionType.vsUISelectionTypeSelect);

    //Clear up;
    if(System.IO.File.Exists(fileName)){
        System.IO.File.Delete(fileName);
    }
}