Forum OpenACS Q&A: Re: subsite security
There is an acs-subsite parameter called RestrictToSSL and it is described as:
URLs we want restricted to SSL. Note that this only takes effect if you have an SSL listener configured on your AOLserver and kernel parameter RegisterRestrictToSSLFilters is set to 1 (its default).You can set in the Site Map (click set parameters). Give it a try.