OPIE S/Key authentication

Hi folks,

I like to implement OPIE / S/Key for authentication to an Apache2 based
(reverse) proxy server (on Suse Linux 8.2 or 9).

I searched the net but could not find any "HowTo"'s for OPIE on Apache.

Can someone please provide me with links where I can find more information..
(what do I need, how to implement). Maybe there is a step-by-step manual
somewhere?

Thanks

Guido