Ok, the string is not held in a textfile where it'd be nice & easy to edit
It's in the ldap tables. The following command will show the sig:
zmprov ga
user@domain.tld | grep zimbraPrefMailSignatureHTML
So I'd assume it'd be a simple matter to inject new text into there from the command line. When I was using the GUI though, I did notice an error informing me that I'd exceeded the 1024 character limit, so this would have to be observed here too I assume.
So, can I make a cool & professional css sig in just 1k of code? I dont know, but it'll be fun trying.
In the meantime, does anyone know the synax of the zmprov command to insert a value into this field?