I don't know whether this is possible - you'd have to check the JIRA API doc details to see if the API supports creation of the equivalent test steps in JIRA.
I did investigate the equivalent thing in the TestRail test management app a couple of years ago and this was one of the problems I found that made it unworkable. The way the TestRail API worked was that you added a TestRail POST request as the final step in the ReadyAPI! test that updated the test result details in TestRail.
HOWEVER - you had to replicate the ReadyAPI! test step details in TestRail for this to work. Also - tests that included a dataloop wouldn't work as the TestRail POST request that was executed once each execution iteration would overwrite the previous iterations execution results.
If the JIRA API details doesnt support creation of the test and step details itself, you're just gonna have to bite the bullet and replicate your tests manually in JIRA as well as ReadyAPI! or toss the whole thing out and rely on ReadyAPI! alone.
if this helped answer the post, could you please mark it as 'solved'? Also if you consider whether the title of your post is relevant? Perhaps if the post is solved, it might make sense to update the Subject header field of the post to something more descriptive? This will help people when searching for problems. Ta