ok, becoming hero sounds nice so I do this for you but... no reliability taken. do it at your own risk:
1. From plesk make a subdomain. In my example secure.finexe.com
2. Goto IIS/websites/the subdomain/properties/directory security/server communications/server certificate and assign a certificate
3.you can also push directory security/server communications/edit and click require secure channel (this will redirect http traffic to error page)
4. make a page that redirects to
https://secure.finexe.com. put it in the errordocs directory of your domain (finexe.com) The permissions are all wrong, you need to set the permissions from the server for your ftp user to be able to put things in the errordocs directory
5. Goto IIS/websites/the subdomain/properties/custom errors you put the 403;4 page to your new redirecting page
now all traffic for
http://secure.finexe.com will go to the https port as well
ok the plesk ip is still available for ssl, it is not aware of what you've done. anyone can still enable ssl for their domain, and you dont want that. be aware what I desscribe here will take down your domain a little while. go and enable ssl in your plesk. Since there is already an ssl configured fo that ip IIS will complain, it will shutdown your domain. Go to IIS/websites/finexe.com (in my case) and enable it again.
ok now you want to split the https to other domains:
I. first we need to know the iusr pass for that domain. well, we don't know that, it isn't anywhere in the psa database? so we need to reset it. Go to my comuter/manage/localusers and reset the password for that user. rightclick the iusr_domainname and chooser set password
II. Goto IIS/websites/domain.com/properties/directory security/authentication and access control, and change the password, click apply and ok.
III. goto your secure domain in IIS e.g. IIS/websites/secure.finexe.com, right click and choose new/virtual directory. Choose the httpdocs directory for the domain you want to have shared ssl
IV. right click the new cirtual directory/properties/directory security/authentication and access control. Se the anonymous user to iusr_domainname and password you had changed to. apply and ok.
your new shared ssl:
http://secure.yourdomain.com/virtualdirectoryname
this will mirror all the domain as secuer.. alternatively you can make a webuser maybe to have both ssl and non-ssl in two different directories.