Prestashop module

I need a new module for a Prestashop site. It's about VAT. ## Deliverables I have a prestashop site. I need a module which modify the price and VAT fields. Usually, you have several VATs in your site, may be for ex 4%, 7% and 16%, and depending of the nature of the item, you choose one of them for each item. This case is more complicated. In front office, the price of one item will be for example $100 without VAT $116.2 with VAT In the backoffice, for a single item we will have: - Part for VAT "a" 4% - Part for VAT "b" 7% - Part for VAT "c" 16% (that VATs will be the ones I had setup before in the back office) So for each item I'll fill three values, one for each VAT. Some values could be 0 if one vat is not going to be applied to it. This will not be applied for shippement or other things not-retaled to the items to be sold. Part-A, Part-B, Part-C will be new fields. The field wich was before price to be filled, will the automatically filled with Part-A + Part-B + Part-C The field wich was before automatically filled with VAT, now will be (Part-A)*VAT A + (Part-B)*VAT B + (Part-C)*VAT C And with this, what we have to do is, in the bill, for example: DESCRIPTION Unit price Total Item number one (VAT 7%) $20 $23.4 Item number one (VAT 16%) $80 $92.8 If you had any question, please let me know. Thank you very much