would probably try leaving out the peroxide 1 part to five parts sounds like alot and it could be affecting them.
dont really thinks it makes a difference wether you soak them or put them in a paper towel to germ they both seem to work fine but you should try to plant them as soon as you start to see a tap root.
you might check the temp of you soil seeing how you are not really having trouble until you put them in soil if its to warm it may be affecting them but they should grow well in a high humidity environment.