i know this is a bit late, but oh well.maybe it will help someone.
start a new text layer and take the fill down to 0%. next, go to the layer style and put the bevel/emboss on. not sure about the setttings, but if you play around, you will get a perfect effect of a watermark.
The watermark i think you are talking about in PS is an add-on (for which you have to pay). What it does is imprint your copyrighted detail into each pixel of the shot so that if someone was to crop off where your name is on the image, you could still prove ownership. You do need PS (and the add-on) to read this data.
The text you are adding on, as mentioned above, is easily cropped or edited of using basic PS tools. I would not bother with the watermark program unless you are concerned about people illegally using your images for profit.
Hope this helps, if not, disregard me as i am no expert.