Imported AD users have "full name" as username preventing SAML from working.

Imported AD users have "full name" as username preventing SAML from working.

I want to use SAML for PMP or at least test how this works for then other sites.

We use WatchGuard Authpoint which lists PMP as supported and even has a guide for setup. All good with setup but on logging in I get "SAML Auth - SAML SSO Failed.". Checking the Audit Log in PMP it shows attempts to login (correctly) with my ad username first initial lastname FLast. Authpoint guide also says to use User Name as the authentication.

I note though then in PMP for my imported AD User it has the username as "First Last" so of course the sent username from SAML won't match. There is no way to edit I can see or change the format when imported.

Why is it importing wrong? What sense is there in this?