I create SSRS report that read data from Sales order in AX 2012.
In my SSRS report I want to calculate Total Amount and VAT for the Sales Order but i can't find where can get the tax for sales order.
There is no simple answer for this, but you should not use the tables your self, but use the class SalesTotals to calculate.
You may also consider looking at class SalesConfirmDP
to see how in does its job.