Ho trovato la seguente soluzione, l'ho provata e funziona.
1) Create your Anchor
2) Publish your article
3) Open up your live article in your browser
4) Copy the URL
5) Create your menu item using an External Link
6) Paste the URL that you copied from step 4)
7) Manually add #anchor to the end of your URL where anchor is the name of your anchor created in Step 1)
Grazie mille per l'aiuto cmq