OpenSEF Component
From Freelock Knowledge Base
The OpenSEF component rewrites URLs with an underlying map of URL to content and Itemid. You can manually change the map to get the desired behavior, though you may not need to if you visit the new page through an existing link or other item in the same category. As I understand it, it's got two basic flows, depending on whether it has a "friendly" URL or a regular Joomla URL.
Regular Joomla URL: 1. Build a friendly URL based on the provided component, id, and Itemid. 2. Store it in the map, with a priority set based on a number of factors, if it doesn't already exist. (if it does, get the friendly URL from the map instead of building a new one). 3. Rewrite the outgoing URL to the new friendly URL. 4. Check the map to see if there are any other items for that URL. 5. Take the mapping with the highest priority, and build/return that version of the page.
Friendly URL: 1. Look up friendly URL in the map. 2. Find the highest priority published item, and rewrite the internal URL to that. 3. Return the corresponding version of the page.
So the critical thing is knowing what Itemid you want the URL to use, and making sure that Itemid has the highest priority. To do that, the category or item needs to appear on a menu somewhere. I often use the "Other" menu for this purpose--add a bunch of links to pages you don't otherwise want showing, just so they will have a valid Itemid.
So with that background, here's what you need to do: 1. If the new item is in a category that doesn't already have a menu item somewhere, create a menu item for the category (or for the static content page, or whatever it is). 2. Find the number in the "ID" column in the Menu Manager for the Itemid you want to use. 3. Go to Components -> OpenSEF -> Manage Friendly URLs. 4. Use the Search field to find the URL to fix (it's easiest to follow the link and get your friendly URL from that link). 5. If you see a version in the list with the correct Itemid but its priority is not the highest, unpublish all the links with a higher priority. (don't delete them--they'll just reappear the next time someone follows that link). 6. If you don't see any items with the proper Itemid, edit any of the links listed, and manually change the Itemid to the one you want, and save. This changes the link priority to 99, and will make that the preferred version.
Note that you can manually create a new link mapping, and even create custom links to arbitrary pages using this tool--it's capable of a lot more. There's also a Google Sitemap generation tool in here--I haven't tried it myself.

