integrating a third party web authentication module

[dmzvpn]

Gurus:

I need to integrate a third party authentication that is web-based (web app; https)
with openvpn. This will replace the standard login page of openvpn (customized version).

'understand issues about api s, recompiling etc.

At this point 'am looking at only browser-based ssl vpn only.

Where do 'start? Any pointers, highly appreciated.

Thanks