Given the time she is waking is equal to her day cycles I would almost bet the problem is due to the 45min naps, if you are putting her down awake, she knows how to get to sleep, she just doesn't have the skills to get through to a new sleep cycle when she wakes from it.
Given her age, during the day, if you can get her to sleep 1.5-2 hours & feed every 4 hours, you will most probably be well on the way to fixing the night waking problem.
Many babies who are 45min nappers are also night wakers as they have not developed skills to "fall back to sleep" & join more than one sleep cycle together.
There is a great post on the naps forum about extending naps, I would have a look at that & see if you can follow it to extend the 45min naps. Once you get that happening you should then be able to see some improvement on the night wakings