I can't help you from experience, but the Vegan Society has quite a lot of material on this--I expect you would already have found it?
http://www.vegansociety.com/lifestyle/nutrition/infants-and-children.aspx
http://www.vegansociety.com/lifestyle/parenting/
http://shop.vegansociety.com/product_info.php?products_id=242
http://www.vegansociety.com/uploadedFiles/Vegan_Lifestyle/Parenting/Babies%20and%20Children%20booklet.pdf
http://www.vegansociety.com/feature-articles/Bringing%20up%20a%20vegan%20baby.pdf
http://www.vegansociety.com/lifestyle/parenting/vegan-babies-and-children/
@Oliver Schick started
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I can't help you from experience, but the Vegan Society has quite a lot of material on this--I expect you would already have found it?
http://www.vegansociety.com/lifestyle/nutrition/infants-and-children.aspx
http://www.vegansociety.com/lifestyle/parenting/
http://shop.vegansociety.com/product_info.php?products_id=242
http://www.vegansociety.com/uploadedFiles/Vegan_Lifestyle/Parenting/Babies%20and%20Children%20booklet.pdf
http://www.vegansociety.com/feature-articles/Bringing%20up%20a%20vegan%20baby.pdf
http://www.vegansociety.com/lifestyle/parenting/vegan-babies-and-children/