If the text is black and the back ground to it wight, its really simple. just use the same texture you use in the color on the transucancy channel. it will not show the shader its in on the wight places and will show the text in black. If your text is not fully black or the back ground not fully wight you might need to ajust it so it is for the translucany map. anything wight will be clear, black will not.

Hope this helps.