OsCommerce bank payment gateway fix

We have a site recently created with OsCommerce for which we've made integration with a Spanish merchant account and payment gateway. All is done, parameters are passed to the merchant account, the connection is establabished correctly but an error is production. The idea is that when users chekckout and select this payment gateway, parameters are passed to the merchant account and the bank's page will be shown in their servers. This is done, but there is some error in the process, which looks like a problem in the encription of parameters, some parameter missing, or the order is missing. We used a ready-made oscommercer integration module for this Spanish bank, it looks like its working, but there is something that we are missing. We have full documentation in English of how to connect with the payment gateway, that should solve the problem if you follow it. Site is [login to view URL] Please, contact me if you are capable of solving this problem. Regards ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform OsCOMMERCE, payment gateways integration