Hi Troy, I've the same problem but with Fortigate UTM with FortiOS 5.2 (latest). The Fortigate UTM is also a integrated controller for wi-fi FortiAP. In the new FortiOs release the vendor support external captive portal for Guest or User authentication, I would like to use Clearpass to manage guest access instead of Fortinet integrated solution for many reason...
The problem is that Fortinet acept external authenticator if their send it back the information's login parameter in a concatenated http POST submit. (I attach to this post an Fortinet internal flow). I'm trying to customize Clearpass Guest Registration portal in NAS Vendor Login but all the test I'v made was unsuccesfull....
It's possible that ClearPass supports Fortinet in vendor settings ? or do you know how I have to configure NAS Login in this case ??
Sorry for my bad english.....
thank you in advance
Toni