Own Captive Portal API usage

[mugosu]

Hi,

I built my own captive portal, RADIUS based. I need to some test results for fortigate. Fortigate 90C - 5.4 version RADIUS auth. tests are successfully and there is no problem 3th part captive portal redirection. 

I want to log on to the live user (RADIUS USERS) via my own portal. 

I can log in Via API on competing devices.(not fortigate)

I need to JSON, web API, RESTApi examples for 3th part RADIUS captive portal user login.

How can I post RADIUS username and password fortigate ?