Combinations of Numbers

There are 7 letters. Each letter represents a number. I need to create all possible combinations to add up to 8. We can use a letter more than once and we can also use a combination more than once if the letters are in different order. A=1 space B=2 spaces C=3 spaces D=4 spaces E=6 spaces F=8 spaces G=1 space D+ D = 8 D+A+A B ............. A+B+D+A SAME LETTERS DIFFERENT ORDER