How do i find which hydraulic line is damaged!

Good afternoon, I have a 2008 328i BMW CONVERTIBLE. Three days ago my top got stuck in mid air. Took it to the mechanic and I was told I have a leak in one of the lines. He aslo stated in order for him to figure out which line is damaged he has  to remove the whole top. Is there any other way that this can be done without removing the whole top. I would really appreciate any information or advice as to how this can be done. I'm really not that comfortable with the idea so if there's another solution please advise me.. Thanks for reading ! ..BTW he wants to start this as early as tomorrow, so I really need help fast...thanks again!!