Debian Configuration :: Replace Snakeoil SSL Certificates?

It appears that on Debian (Squeeze) that when I install Postfix MTA, it looks like it uses a default Debian SSL certificate:

root@mail:~# postconf -n | grep -i snakeoil
smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key

My question is it safe to remove these and re-create my own with openssl?

cd /etc/ssl/certs
openssl req -new -x509 -newkey rsa:2048 -days 3650 -keyout mail.key -out mail.crt
openssl rsa -in mail.key -out mail.key
mv mail.key /etc/ssl/private

Will this impact my Debian system any or will it work fine? Do you guys have any experience with this? I would rather try generating them myself and change it from 1024 to 2048.