Problems with products entered before uc_vat installation

Hello,

uc_vat doesn't work correctly with products which are entered before uc_vat installation(with Store owner will enter prices inclusive of VAT. selected). I have to open all products and save them. Also in my db all products are entered with VAT. When I open them (after uc_vat installation) to all prices vat is added, so I have to change them back to old value and save. When I do this everything works perfectly. But there are more than 200 products.
Maybe I can write some custom script to fix these "old products"? I've tried to analyse uc_vat_nodeapi, but I don't understand why it behave in this way.