Apple Pay CSR Invalid

Does anyone know if there is information just inherently missing from the Onboarding document re: generating the correct certificates on both the Moneris and Apple side of things?

https://developer.moneris.com/Documentation/NA/E-Commerce%20Solutions/Apple%20Pay/~/link.aspx?_id=A37C03D962C3424FA247FF859B2C08E7&_z=z

Every time I try to upload the .certSigningRequest file to create the cert in the Apple Developer Portal, I get told by Apple that it's invalid. Does Vendor ID mean Merchant ID?

halp!