Why not add update as an action.
I think this can be implemented quite easy, as there is already the sugoi mass-update-page. Just get the ed2k-links from the checked files and put those automatically as value in the mass-update text-field for the ed2k-links there. This feature would be useful, as you do not always have the ed2k-links of the files you want to update (storage/source/comment) in a copy-and-paste-friendly version.

PS the mass-update-feature schould not be replaced by this. It's just an addition to user-comfort.