Reading between the lines. You need tasks to appear in the Gantt chart before the start date of the project. You'd like those tasks to appear as -W1, -W2 on the Gantt chart.
I just tested with Project 2013 Pro 15.0.4823.1000 and they appear as you need in both Print Preview and on screen. What release of Project are you working with? An update may be in order:

https://blogs.technet.microsoft.com/...pport/p/msp13/