Assuming you are it is less aggressive than say Tifway 419.

If the Centipede has a loose canopy you might get away with just seeding into the Centipede and letting the Bermuda out compete the Centipede.

If you want a little better coverage you could use a weed killer such as Roundup, wait for dye back, and then seed.

I would also check into seeding rates, and germination calculations. These are very important to consider when seeding. The germination will be calculated from your bag of seed and helps determine which one to buy. Seeding rates are like they sound. The rate at which you apply the seed to your lawn. It varies with seed size, and how much coverage you want. It also is important to know your germination before you set your rates. If you only get 50% germination from the bag you are going to want to have a much higher rate than say a 90% germination.

Hope it helps.