I am a licensed marriage and family therapist and a licensed professional clinical counselor on self-motivation and willingness.
The first part is to identify the willfulness to resist doing the homework. This is important since you cannot change something you are unable to observe.
The next step is to label it as for example resistance.
The next step is to identify the opposite of resistance which is for example acceptance or willingness.
Make an inner commitment to notice when resistance is preventing you from doing the homework and practice taking a step toward willingness, this will take time before results occur.
Do the opposite action of resistance which is to participate in the homework and urge surf through the desire to follow resistance. Notice the urge to resist and turn the mind toward the willingness to approach versus avoid homework. Develop a cope ahead plan when you feel the resistance coming on and how to remind yourself to turn your mind toward willingness. The key is to do the opposite action of resistance to train your mind on approaching versus avoiding. Once you practice this over time, you will experience a decrease in avoidance. Practice, practice and more practice.
I hope this helps. I can clarify and add more.