Lets say that I create a constant raster with CreateConstantRaster function. Then I want to set values at certain positions. For instance set the value at the index position (3,2) of the raster to a certain value.
I have never done this before, but you MIGHT be able to convert the raster to an ASCII text file then open the text file in Notepad, make your edits, then convert the ASCII text file back to a grid???