Rick, I struggle with this every year. There are good publications available on the IRS web site and several companies that will calculate the maximum amount for you for a reasonable fee.
I know the 2106 form is involved and you are looking for "Expense in excess of reimbursement" so you are on the right track. I always get screwed up in the middle of calculating the deduction so I usually end up plugging away in Turbo tax until I see the refund increase.
Sorry I can not be of more help but I have not started taxes this year yet.