@Andrew0409 is going through a similar process now and can maybe shed some light.
To my knowledge, they bring your outside credentials into consideration after your entrance exam. So, make sure you score well on your entrance exam to be placed in alternative services.
A friend who went through the process about 3-4 years ago claims that the exam is only in Chinese. He enrolled in mandarin classes at NTNU (Shi Da) before getting his enrollment letter and stated that he wanted to score well on the exam in order to be placed in a good alternative service.
Since he went to an intl high school and also had a BS from a university in the states, he got placed in Jia Yi to teach English to underprivileged kids.
Best you clarify if you can take the test in English or if you even have to take a test anymore through enrollment since policies tend to change every other month.
Hope that was helpful, good luck!