Hi M.,
I'm sorry to hear about your difficulties with napping. I still have issues 3-4 times a week with my 11-month old and her afternoon naps!
Have you tried nursing her to sleep? Will you let her sleep on you if she falls asleep nursing? My daughter still nurses to sleep and after 10-30 minutes or so of sleeping on me, I can usually put her in her crib. It takes a while for them to get used to this change, but eventually she'll catch on.
Also, she may also just not be ready to sleep in her crib for naps. I know this may not make sense if she is sleeping there at night, but my daughter was the same way for a while, at least until 6 months. Many babies still need Mommy and while I know this is not ideal, she may just miss you or want to be near you to sleep during the day.
Also, I suggest reading Dr. Sears' Sleep Book or Elizabeth Plantley's No Cry Sleep Solutions. I believe the latter describes extensively how to make the crib a cozy and more desired place to sleep, such as using loveys and music, etc.
I'm not sure what you've tried already, but those books really helped me. One thing they really stress is making her pre-nap routine like her pre-bedtime routine, only shorter. Have you tried giving her a bath beforehand?
Also, I know a friend of mine has a baby who does not give her sleep cues, so this can be tricky. A lot of it is timing and I've heard that babies should go no longer than 3 hours between waking and sleeping--but some do go down earlier. It may just be a matter of trial and error.
Good luck and I pray she'll sleep for you soon!
Take care.