Make a small piece of text on a bitmap editable

Attached is a bitmap file used as a background image for our product's GUI. If you look closely at the image of the keyboard visible near the bottom, you may notice that keys read "JET 4 8", which are the product's (short) name and version number. This image was created by a freelance designer many years ago. He used Photoshop, which we do not have, so we have always had to ask someone to update the version number. You have to erase the version number in a bitmap editor, import the resulting image into Inkscape as an embedded bitmap, and add a text object with the right color and effects, so that we could easily edit the version number in the future. I can provide the original Photoshop file to the winner upon request, if that would make things easier. Please confirm that you are proficient in Inkscape when bidding.