TextMesh Font Materials Not Editable?

This seems very simple, so I feel I must have done something wrong.

I simply want to fade up a TextMesh from black (alpha 0).

I know that I can change the color values (including alpha) using material.renderer.color. However, I want the TextMesh to BEGIN at alpha 0. Simply setting material.renderer.color, whether in Start(), Awake(), or Update(), results in the text flashing on screen for a moment before going black.

So obviously I should simply click on the color in the font material, and set it's default alpha there, right?

But I can't, because the font material is not editable. It's grayed out, so I can't edit anything about the material. I can duplicate it, and then associate the new material with the texture - but I can't then assign the duplicated material to the TextMesh and delete the old one.

What's going on here? Why are font materials not editable through the editor panes?