Self-signed cert: Can I change the expiry to be more than 1 year?

[Paul Crick]

It's that time of year again when I need to re-generate my self-signed certificate (mostly used for mail access via SSL than any hosted websites).

Using the "generate self-signed cert" option in Plesk, it generates a certificate for a year. Is there any way to increase this? Tweak a parameter in the psa database? Tweak a script file somewhere? Or do I have to resort to some command line magic to do all the steps manually then integrate with the PSA database accordingly?

Thanks in advance
Paul