2
in system templates (root/modules/system/templates/blocks/) is a file "system_block_user.html" see on it!
In line 9 you will find this:
Quote:
(<{$block.new_messages}>)
now just edit
1. remember about refresh your system module
2. if you have duplicated (or cloned) yourtemplates just edit it in template menager (it's easier and faster!)