ObjectServer REST API over HTTPS support using CA signed cert on OCP Platform

Product : Watson AIOps 2.1 Event Manager (NOI 1.6.3) on OCP
OCP : 4.5

(1) PoC Customer (i.e. US Tier-1 Telco) wants IBM to enable HTTPS for ObjectServer REST API instead of HTTP. At present, ObjectServer HTTP REST service has been exposed and HTTP works well with no issue. https://www.ibm.com/support/knowledgecenter/en/SSTPTP_1.6.3/com.ibm.netcool_ops.doc/soc/integration/task/expose_objs_port.html is used for reference to enable HTTP.
There's seem lack of documentation for enabling ObjectServer REST API over HTTPS and how to extract SSL cert and import SSL cert to OCP configmap.
The closest KnowledgeCenter doc which indicates enabling ObjectServer REST API over HTTPS is https://www.ibm.com/support/knowledgecenter/en/SSSHTQ_8.1.0/com.ibm.netcool_OMNIbus.doc_8.1.0/omnibus/wip/api/task/omn_api_enableinterfaces.html and it's meant for on Prem.
Section 3 of the Knowledge Center for Object Server on Prem indicates :
If you want the interfaces to be active on an HTTPS port on 9090, set the properties that are shown in the following example.
Because an HTTPS port is SSL encrypted, a certificate file that contains an appropriate certificate needs to be created and protected by a password.

NHttpd.SSLEnable : TRUE
NHttpd.SSLListeningPort : 9090
NHttpd.SSLCertificate : “certificatelabel”

(2) On top of ObjectServer REST API over HTTPS on OCP, the PoC customer requires CA signed cert and not self signed cert for interfacing with their ServiceNow ticketing system.