Adding custom path to Avast! File System Shield exclusion list

How can I add a custom path (e.g. /usr/local/…/something) to the Avast! File System Shield exclusion list???

So far, I have not magaged but to add only specific items from the graphic/object window, which opens on hitting “Advanced” File System Shield options, and then “Exclusions”.

It adds the chosen object (non editable) path, but the path I want to add, does not correspond to any object in that window.
Or, anyway, I have not found out how to specify the path I want…

Edit: Post below resolves the issue.

In the open dialog of Avast preferences press CMD+SHIFT+G (as in Finder) and type a path to folder