SAML Authentication with ADFS - domain\username

SAML Authentication with ADFS - domain\username

We have an Active Directory with a different UPN and samaccountname. With the AD connection i can login to Servicedesk Plus, but when i enable SAML it only logs it in with the sammacountname part (username) without the domain (domain\username), hence a new user is made. 

Is there already a solution for this ?