By law what can SC child support use as income when it comes to military pay?

I married my husband about three years ago. He had two children who lives with there mom,and I have three children who lives with me and my new husband. After 2years he got deployed for 15months. The ex-wife heard how much army makes when they are deployed and she took him back to court for a increase while he is in Iraq.They were so kind to set his court date when he came home for RR. Now he is paying over $1,000 a month child support. My biggest problem is he is a E-6.Child support used everything on his LES to determine his amount to pay.The order is from SC,but we are currently stationed in Hawaii. They used his base pay,hazard pay,separation pay,food allowance,cola,BAH everything. My husband gets as much as he does because he claims me and my three children as his dependents. Which in a sense is for me too. SC cant use my income to determine his child support,so how can they use everything the army gives me and our children to factor into the child support? They figured his income over $7,000 a month when his taxable income is only a third of that a month. Some one please help us get out of this mess. They are really trying to stick it to my husband.