You are free to issue and reissue SSL certificates fairly effortlessly @mits but it is a bit of a hassle. Note that your website will be not have a SSL while changes are pending.
In a situation where you need multiple protected directories I advise either a Wildcard SSL, putting your test website on test.yourdomain.com or a Protect multiple website SSL and protect multiple domains. Best for you depends on of you have one domain or multiple domains. Does that clear things up?
roy darling *my posts seem a lot shorter in my head