We need to reference our internal job ticket number against the project for billing and invoicing, the project key would be the right place to include this number as this is also referenced against issues.
The format for our numbering system is YEAR |CLIENT CODE | JOB NUMBER eg 14MAC4021 so we need to include this against the project to easily track jobs, however the project KEY is limited to letters only. Is there anywhere else we can add this number against a project so we can filter issues and timesheets by this number.