Hello,
unfortunately there is only 4 signatures per user. Some of my users, needs to set up more the 4 singatures. They got some forms of messages for sending to theis customers. So, the best option would be possibility to set in webadmin per domain the number of signatures.

Or, another option, the mail templates, that could be predefined by user and in creating new message, user could use that template to send out the mails.

Best regards,
MJ