My daughter resisted milk at first. So I just started mixing the teensiest amount of milk in her formula. Like less that one ounce at first. And just gradually upped it over time. And now she'll drink a bottle of reg. milk no problem.
The bottle part is a little more tricky for me. I admit, my 18 mos old still gets a bottle of whole milk before bed and not a sippy. She is a strong girl and I figured it's not the end of the world. She'll scream for hours if I give her her milk in a sippy and then be up crying/ hungry half the night. But during the day, she is fine with a sippy (for juice, water).