This information may come too late to help you but you can do this with a change to Moodle to include the WordPress hash function.
Caveat: Modifying Moodle isn't generally recommended, changes may delay updates being installed and the changes must be re-applied as part of the update. When you modify Moodle it's more difficult to get support, either in these forums or elsewhere, as your Moodle doesn't match anyone else's.