P.O report with discounts

Hi,

i need to develop a report which displays PO details from EKKO EKPO and EKKN based on Company code, purch. org, pur.grp, vendor, PO date, PO, cost centre and Material group.

I need to display details of PO along with Gross value, ***discount value, netvalue, tax code and tax amount.

1.How should i get the discount conditions and to cal. the discount value.

2. whenever i sort the report by Purch.org (or) purch. grp (or) Company code the report needs to be realigned accordingly w.r.t Gross value, discount val, netvalue, taxcode & tax amount.

your suggestions will be rewarded.

BR,

ravi.