Import SAML client with certificate and signing key

I am using Keycloak import strategy were I am importing Realm from JSON files. For OIDC clients there is no problem, I can configure ENV variable and replace placeholders for secret and all sensitive data per environment.
But now I have to import SAML protocol client, and there are:
saml.signing.certificate
saml.signing.private.key
which needs to be different per environment. And when I created client on UI in test purposes, I got generated values, but now from my JSON import file, how I can generate values and have them in exposed as ENV vars or auto-created like creating from UI?

I tried to import it completely without any key:value pair hopping that Keycloak will import them, but nothing happened, there is no values generated.
But when we crate client from UI we also do not define values but values are present.
Any ideas?