Check with your developers. We have something similar where users access their profiles through their web browser.
When they click on the save button a new document is created in the registration database, and a web query save agent then uses that document to update the Domino Directory. This method allows us to maintain strict security on the Domino Directory, while allowing thousands of users to change such things as internet passwords, phone numbers, etc.
This was originally set up before I took over administering these servers, but I beleive the registration database was created with a standard Lotus template. We have made many modifications to it since then as well.