Inquiry regarding indirect export processing for software production

We are a custom software development company in our second year of business. To explain our transaction structure: our company (Company A) develops software programs, which are then supplied to a domestic company, Company B (the exporter), who subsequently exports them to an overseas client, Company C (the orderer). In other words, Company A receives orders from Company B to produce and supply software, and Company B exports the supplied programs to Company C. Therefore, we would like to request a Purchase Confirmation from Company B to record this as an indirect export performance. Our questions are as follows: 1. Is it possible to process the production of software programs, which are not physical goods, as an indirect export? 2. If indirect export is possible, is it correct for us to issue a sales tax invoice (zero-rated) to Company B and request a Purchase Confirmation? 3. In order for Company B to issue a Purchase Confirmation to us, what are the required documents and the specific procedures for submission to Korea Trade Network (KTNET)?