I made this touchmark myself. You should be able to make an anvil with your initials in it. Just cut off, or grind flat, the end of a punch or chisel, and use a zip disc to carve an anvil shape on the end (carefully). It took a little practice, but I was able to make the hammer shape without too much difficulty. Carve the anvil without heating the blank. Then heat it to a lemon yellow and use reverse-letter stamps to put your initials in the center of the anvil (hold the stamps with a vice grips). You can buy individual reverse letter stamps. I don't remember where I bought mine, but you can Google for vendors that sell them (there may be a minimum $ amount for the sale).
If the reverse letter stamps are cost prohibative, you might be able to use regular letter stamps to make your own reverse letter stamp with your initials on it (both of them), then use that stamp on the anvil. I've thought about doing it, but haven't gotten around to it. The looks of the letters in the anvil would be different, but if you are successful, it might just look cool.
After punching the letters, heat treat.