In some sets of rules of origin there is a provision which impedes to use duty drawbacks systems on the materials imported in the beneficiary country/partner country that are used in the production of a good intended to receive preferential treatment into the EU.

Duty drawback systems are all those mechanisms permitting not to pay at import or to recover the duties paid at import on the materials that are used for further processing while final good using those materials is exported.

You need to verify the specific conditions on this issue and documents needed to demonstrate the fulfilment of this rule contained in the relevant set of rules of origin.