License Request Decoder does not decrypt Axinom FairPlay Streaming requests

[truedread]

On the license request decoder page for FairPlay Streaming, the RSA private key field says:

The RSA private key of a license server (PEM-encoded, in the PKCS #1 format), which is required to decrypt the license request. It's optional, if the license request is generated for the Axinom's license server.

However, when supplying a license request generated with the certificate from my DRM evaluation package (located here), it refuses to decrypt the request saying it isn't an Axinom certificate. Is there some other Axinom certificate the decoder wants?

[AxinomSupport]

Hi @truedread,

In the attached location, we can see that your Application certificate is available. But the RSA private Key field requests for the private key. You can refer to our portal document, https://portal.axinom.com/drm/documentation/fairplay-and-axinom-drm#_obtain_the_fps_customer_data for further understanding.
Also you can raise any query to support@axinom.com.
Thank you.