Support numeric value in Registered claim 'iat' in JOSE DataPower library

The IBM DataPower JOSE library does not support numeric values for registered claim ‘iat' according to the spec.
We are required to use ‘iat' during Message encryption which uses a JSON Web Token (this must be a JSON number representing the number of seconds from 1970-01-01T0:0:0Z as measured in GMT until the date/time) for encrypting the message during the external communication. There are various claims in the JWT protected header and one of them is ‘iat' and it needs to be set to numeric value and JWT spec clearly mention that as well . https://tools.ietf.org/html/rfc7519#section-4.1.6 Unfortunately, DataPower does not support numeric value in ‘iat.

If a numeric value is supplied - the JOSE library throws an error when parsing it : mpgw (JWS-Encryption): request POC0JWS_Encrypt_JWE #2 gatewayscript: Transforming the content of INPUT. The transformation local:///JWE_Encrypt.js is applied. The results are stored in PIPE. failed: jwe-encrypt error: TypeError: Invalid type 'number (1579623770)' detected on method invocation. Method name: setProtected; Parameter index: 1; Expected type: string): jwe-encrypt error: TypeError: Invalid type 'number (1578983321)' detected on method invocation. Method name: setProtected; Parameter index: 1; Expected type: string (from client).

Similar issue with other element called http://openbanking.org.uk/iat was fixed under the RFE https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=131757
We request the similar fix for ‘iat' claim as well, so that we can continue to use IBM DataPower gateway for all encryption and decryption requirements.