Unable to renew Supplier certificate XML PO Wallet manager 12.1

Hi I've been given a certificate bundle from a Supplier which includes;

VeriSign Class 3 public Primary Certification Authority - G5

     Symantec Class 3 Secure Server CA-G4

          And the Supplier Certificate

I'm using wallet manager 10.1.0.5.0 which is bundled with E Business suite 12.1.3

Verisign's certifcate imports successfully however not the Symantec one.

I keep getting

"Some Trusted Certificates could not be installed"

Any ideas? I've tried creating a brand new wallet and removed all of the trusted certificates and get the same error.

Without this certificate all of the PO's from the supplier are failing in the XML gateway