PART WISE TAX in AR INVOICE ENTRY

suppose I have 2 parts to sell. Part A is having tax 5% and Part B is having 10% tax. How to do settings for this, so that it will be called in AR Invoice entry linewise? I have created 2 product tax category along with tax types and attached it to Part master. But tax is not getting calculted. While I have created Tax liability and attached it to Customer master. When done invoice entry tax liability tax is getting calculated at customer level. My query is to get tax calculated Part wise, Please suggest how to do it?

I am curious, are you by any chance using the Avalara product to calculate the TAX?

No, Wanted to use default tax system in Epicor.