I would not not not feed a baby soy formula (unless it is truly medically necessary. For instance because the baby has a congenital lactose intolerance—which is VERY, VERY rare and diagnosed in the testing they do right after birth). There is mounting research that soy formula can cause harm to a child's developing endocrine system, could be linked to ADHD and early onset of menses in girls and early formation of breast tissue, and that soy formula might have dangerous levels of aluminum and manganese.
In the U.K., Isreal, France, and New Zealand they have severely restricted or banned the use of soy formula for babies because of the mounting research on the adverse health effects. In the U.S. and Canada, the outcry has been much weaker and slower in response, but nevertheless, the American Academy of Pediatrics has updated their stance on the use of soy formula to be far more restrictive and cautionary than before. First, they remind readers that: "The AAP is committed to the use of human milk as the ideal source of nutrition for infant feeding." Then, they go on to say that despite there being very few cases when using soy milk is really indicated medically it still makes up more than 20% of formula sales in the U.S. (REMEMBER: your baby isn't lactose intolerant and you just don't know it--remember breastmilk is very high in lactose so a truly lactose-intolerant baby would have never survived its first few weeks of life until very recently). The AAP goes on to acknowledge the: "potential harmful effects of soy protein-based formulas and the phytoestrogens they contain."
They conclude by saying that you should NOT feed your baby soy formula unless it is truly necessary (either medically in the case of a diagnosis of galactosemia or hereditary lactase deficiency" or if parents insist on soy due to religious or cultural beliefs against all animal products.
I am also concerned about you feeding your child juice. Juices are hard to digest and are usually discouraged for babies as they can also cause other problems.
As for other things to consider, I am attaching some information for a blog I did on the subject. My suggestions are that you
1) change your formula again. You want something milk based and organic. Also, there are other things you want to watch for in formula e.g. BPA (leach from cans) and I think hexanes... I am going to do a bit of research more on this for you. I have somewhere the information on the baby formula that is commercially available that many researchers I have worked with consider to be the healthiest (least BPA leaching and fewer contaminants) . I will find that and send it to you.
2.) supplement your formula. There are things you can do to make the formula healthier for your baby. This includes adding probiotics and maybe some good cod liver oil. There is more information on this below.
3.) see a naturopath. If you can find a naturopath, they might be able to recommend other very gentle, energetic, or natural ways of working with your baby. At my house, I have had great success with homeopathy with childhood illnesses, including gastro-intestinal upset. As well, I take both of my children to naturopaths which have helped with everything from extreme growing pains in my oldest child to the occasional cold, etc. If you can't find a naturopath near you then a homeopath, a chiropractor that does AK and nutrional work, an acupuncturist, or a midwife are all trained healers that might be able to offer help. You should feel free to call these people and aks if they feel comfortable working with infants before booking the appointment.
4) there other other home remedies that I have heard of helping babies with colic or intestinal distress. Most of these I am familiar with are for the moms to do when breastfeeding, but I know there are others that can be done directly with the baby. Small amounts of fennel tea are one thing I have heard--you might as the naturopath about that. Also, massage with particular oils (Weleda has one for baby's sore tummy) are all supposed to help.
5) there is also research that carrying babies like in a sling or baby carrier for more hours of a day can help them with colic-like symptoms. This might be able to provide some relief in your situation.
I think if your instinct is that something is hurting Aubrey that as the mother your instinct is probably right. I also think that your instinct that the food is the problem is probably right. I would start with changing the formula again, doing healthy supplementation (like with probiotics), and then getting the support of a healthcare professional actually trained in dealing with nutritional and healing challenges of babies.
Here is the information on my blog....
Tips for healthier bottlefeeding
1. Find safer baby bottles, either glass or bottles marked BPA and phthalate free.
2. If you have to use formula avoid using the liquid formula which is associated with higher levels of BPA leaching.
3. Always use clean, filtered water. (Try to avoid bottled water.)
4. Buy organic formula (babies cannot detoxify like adults and pesticides present a heightened risk to developing brains and bodies).
5. Look out for added sugars, like sucrose, in infant formula! (Similac's organic formula has been caught using sucrose–i.e. cane sugar–instead of lactose.)
6. Consider making your own formula, or supplementing your powdered formula. (This isn’t for everyone. You should talk with your doctor, midwife, or other nutritionally-savvy healthcare professional first. Here are some websites to help: http://www.westonaprice.org, http://www.mercola.com, http://www.kidsorganics.com. REMEMBER: Soymilk and rice milk aren’t fit for babies and straight cow’s milk isn’t enough alone.)
7. Remember that nursing isn’t just about breastfeeding, it’s about bonding, loving, and nurturing. All this can still be done when bottle-feeding.
8. There are breastmilk banks that can provide supplementary breastmilk (e.g. in the case of a premature baby, twins or triplets, a health situation for the mother, etc.).
I hope that helps.
I will do more research on this for oyu too. Also, I might post this on my site but will change your name. Let me know how this goes and if there are any improvements.