Reporting for messages sent via trigger are visible in two places. The first is the traditional "View Reports" page. The second is on the trigger description. Viewing the reports from here will allow you to see the reports relevant to the tr you select. To do this, follow the instructions below:
1) Click "Create/Send"
2) Click "Triggers"
3) Click on the trigger that you'd like to view the report for.
4) On the right hand side click the report that you would like to view.