Case number in worklow / mail template

hello,

I have a problem with the case number in suitecrm.
If I want to set it in a template with $acase_case_number it is blank.

The case already exists and the number is displayed in the module.
Also I can’t set the number as a condition in workflow.

Anyone can help me?

Thanks!
Testes

How is this being sent out?

By a normal case, report, case update etc?