Buying SSL to secure my email - NOT using HostPapas!

Hi, a couple of my clients are constantly moaning about the security popup in Outlook when accessing secure email using HostPapas self-signed certificate. So in response to this and to try and keep their business I've been trying to ask Hostpapa whether buying and installing my own SSL certificate will let me offer my clients the same secure email access but without the security popup. I'm well aware of the advice about installing the hostpapa cert locally, etc.. but this does not fix the problem in Outlook where the user still needs to hit YES every time, and anyone with fussy clients will understand how frustrating this is for me to deal with on a daily basis.

Sorry to post here about it, but I've been trying to get this sorted through a support ticket and it's taking to long.

Lee