[V8i Ss3] How can one modify a "built-in" toolbar?

It looks like it's fairly straight forward process to modify a menu item so that one of your dgnlib's menu items replaces a built in item.

For example, we use a MVBA to create new files according to our File Naming convention and to also set a number of default settings and reference files in the process. So our File > New... menu supersedes the delivered version's File > New....

We'd like to also do the same with the Standard tool's New... icon.

So far, the only method we have found is to create a whole new toolbar, but then it is not recognized by the Tools menu as the open "Standard" toolbox.

We did this with the Primary Tools and that's what we see within the interface.