try to get the baby to an rabbit -saavy emergency vet; this is life-threatening in a rabbit that young.
you can give a probiotic like benebac , better to give pedialyte rather than the home made recipe
The best thing that you can get is the biosponge which will bind the toxins in the babies GI tract
Many people who own horses have this product...
here it is advertised in a smaller amount for dogs/cats.
http://www.entirelypets.com/platbio15cc.html
Randy, our wild life rehabber mod ,has saved many young animals with this product.
In a rabbit this young the ph of the GI tract is not stable and is very easily thrown off balance . When this occurs toxic bacteria like clostridium proliferate and the rabbit has little chance of a recovery without a lot of assistance
I have never treated a rabbit with the Dana Krempels protocol although she is a very reliable source; I know that you do not have access to everything prescribed here.
http://www.bio.moiami.edu/hare/squirts.pdf
Some folks will feed an young rabbit the cecal pellets of another healthy rabbit (without breaking the the thincoating covering the cecals. )
Iwish we we could help you more
Iam transferring this thread to the Infirmary