Virtual hosting means multiple domains, so you might be out of luck unless it is possible to load multiple nsssl modules each listening on a different ip. (Has anyone ever tried this?)
However, one ssl module can be used if you don't mind the browser popup warning of a domain name mismatch for one or more of the domains.
My VAT module has instructions for hosting more than one domain from one OpenACS install. Just keep in mind that aD never did anything to help with this situation. You can get a current copy of the VAT at: http://zmbh.com/discussion/vat/. Feel free to bug me over any install problems. As an example of two servers sharing one OpenACS: http://saleonall.com/ and http://stellardata.com/