Normally, If the divorce decree or separation instrument provides for "family support" but no amount of the family support is designated as child support, then the entire payment is considered alimony and hence is deductible. So the amount paid will be deductible for alternative minimum tax purposes too.
Amounts paid under divorce or separate maintenance decrees or written separation agreements entered into between you and your spouse or former spouse will be considered alimony for Federal tax purposes if:
If you and your ex can agree on considering the entire lump-sum payment as Alimony than this would be the most tax effective way of doing things
So this would be deductible for AMT tax calculations as well?