Sorry to hear you are having a difficult time detangling your daughters hair. I know it can be very tough on her (and you) to have to tug on her hair to get rid of the knots.
Since you mentioned that California Baby did not work on her and she has eczema, I looked up a natural product.
I found Earth's Best Organic Hair Detangler which is a spray but should not be harmful to her skin. Then I also found some homemade recipes for you to make your own detangler at home if you'd like. You can find two recipes here: http://www.ehow.com/how_5906992_make-natural-organic-hair-detangler.html
If you find that both may be too harsh for your daughter, try the Earth's Best formula first to see if it will help. Also, I know you said you tried California Baby-- have you tried applying it at night and wrapping her hair with a shower cap then detangling in the morning?
Hope this helps