Pro6PP OpenCart plugin Opencart integration instructions Download at least the required modules. Install vQmod (required). Install Dutch language extension (optional). Install Pro6PP vQmod extension (required). Make the postcode a required field for Dutch addresses. In your OpenCart admin panel, go to System -> Localisation -> Countries Edit country 'Netherlands'. Enable 'Postcode Required' and click 'Save'. Follow these steps to setup the Pro6PP vQmod extension. Unzip the Pro6PP vQmod extension and put these files in your OpenCart folder. In your OpenCart admin panel, go to Extensions -> Modules. Install the Pro6PP module. Edit the Pro6PP module. Fill in your Pro6PP auth_key. Click Save. You're done!