System login via AD credentials

I have recently updated my EdgeMAX EdgePro router to 1.9.0.  I have successfully set up system login so that i can use my Active Directory credentials to manage the router.  The only problem is that i have to enable PAP in my network policy that allows the credentials to be used.  I really dont want to use PAP and would like to use CHAP, MS-CHAP or other authentication method.  

The reason i updated to 1.9.0 was because i read somewhere that L2PT RADIUS could be told to use a certain type of authentication and I ignorantly assumed that the system login would use the selected type also.  

Can anyone tell me if this is possible or not, and if so what am i missing?  

Thanks!