It's actually a pretty simple method.
-Start out with your texture (For best results, use a 512x512 or 1024x1024 size and rescale it later).
-Go to the preset shapes option and select the circle and draw it on the map.
-Select the text option and move the cursor over the circle to where it turns into an A with a curve.
-Click on it, then type in your text making sure to adjust the "Leading" so the registry expands outwards or inwards.
-Hit "OK" when finished, then go to "Layers" and hit "Convert to Raster Layer" and select the circle and delete it.
The above works fine for the bottom regs, and if you want top regs, simply mirror the circle *before* adding the text.
You can tamper around with the settings, circle size, font type, etc. and get various results and improve your techniques.