Okay - good to know. Here's a trick. There is a children's clothing store called Hannah Andersson - European clothing. They sell clogs and those clogs will give you an extra 1 1/2" in height. I do NOT recommend it for little kids but the older girls should be good with it (my 2 year old is 40" now and she can't walk in shoes like that just yet, I've tried, safety first), they have great arch support and are really comfortable. Just in case bring another pair of comfy shoes. For older boys needing that height you can usually find a pair for boys that add about an inch at Nordstrom.
The clogs for girls need to be ordered and you should figure about 3 weeks to make certain it will work and your order get to you.