Project to provide modifications to the tax calculations in OsCommerce.
OsCommerce allows for making an additional cost for products, for example - say the cost of an shirt is $10 you can make an additional charge for an option so if the customer chooses the shirt in extra large then you might charge $2 extra, that is fine but my customer has items which are VAT zero rated but the options on them are not zero rated so we need to charge the $10 at zero rate tax but the $2 at 17.5% tax, the option is always at standard tax but the item may or may not be zero rated, but we need to be flexible enough to allow for all scenarios
OsCommerce doesn't allow for this, it works by applying the same VAT rate on the option as that applied to the item, I've already made the change on the admin side to allow variable tax rates on options but this now needs to be incorporated into the vat calculations in the shopping basket and the checkout pages.
This is a tricky one, I need someone who -
1. Understands in detail the inner workings of OsCommerce.
2. Is sufficiently experienced on the business-side to understand what I'm trying to achieve
3. Can work professionally using source-code control and provide a documented solution (in English),
Don't come to me with 10 minutes of programming experience