We've already upgraded to 2048 bit SSL certificates in Ability FTP Server 2. We are also planning to add this to Ability Mail Server, probably in the next update which should hopefully be in the next month or two. Ability FTP Server should also expect an update around the same time.
For now, you can install and use Ability FTP Server to generate your certificates or if you don't want to do this use Ability Mail Server to note down all the fields and send me your fields to
chris@code-crafters.com and I'll use Ability FTP Server to generate you a certificate, key and signing request.