SSL certificate for Horde mail in Plesk

[brainforge]

I have created a self-certified SSL certificate and assigned it to the panel, my domain and a subdomain.
Certificate is used for:

https://mydomain.com:8443​

https://mydomain.com​

https://mysub.mydomain.com​

Using Firefox for those I get a security warning as its self-certified - no problem there.
Firefox says the certificate is for mydomain.com - that looks good.

But when if try to access horde using:

https://webmail.mydomain.com​

Firefox says: The certificate is only valid for Parallels Panel
That's not what I want to see !

How can I get webmail / horde to use my self-certificate?
Presumably the same issue would apply if I purchased a certificate for https://webmail.mydomain.com
But as the self-certified does not work purchasing one sounds like a waste!

 

[abdi]

A little search on the forums should lead you to that answer ..That query has been discussed here by many!

 

[brainforge]

A search for 'SSL certificate for Horde mail in Plesk' produced this:

http://forum.parallels.com/pda/index.php/t-88183.html

I'm on a new Plesk 11.5 installation.
That post is over 4 years old and refers to Plesk 8 and 9.
It also refers to /var/www/vhosts/sub.domain.com/conf which is not where Apache webmail configuration resides.
Looking for some up to date suggestions, thanks.