Here's why you can't use a reflexive verb for "doing my homework":
* The action isn't done to the person: You're not doing something to yourself when you do your homework. You're doing something to the homework itself.
However, you can use a different phrase to express a similar idea:
* "I am applying myself to my homework." This implies you are actively working on it and focusing your effort.
* "I am working on my homework." This is a more direct and simple way to say it.
Let me know if you have another phrase you'd like to translate!