How do I render tif sequence without file extensions?

Mac OX 10.6.8

2x2.93 GHz 6-Core Intel Xeon

64 GB 1333 MHz DDR2

Master Collection CS6

Used to have a template built to allow me to render tif sequences for our Weather Center without the file extensions.

I got it to save the new template without, but when I try to render it puts it back in.

Has something changed, or have I just forgotten how to do this?