Question re: Thai Pads

Correct me if I am wrong but the proper way to kick is to bring the knee up to a 45 degree angle and then turn it over and strike down on an opponents thigh, midsection etc. How is this possible when kicking thai pads? I find it very difficult as your partner is most likely holding them at an awkward angle for you to turn your leg over and strike down. I may just be way off base but it just seems very difficult for me to use proper form to kick thai pads unless the are held quite high (after I have done stretching, lol). Advice/input is appreciated.

There are many different angles to land that kick.