You are right, these methods are missing. Could you file a bug report in our forge?
I’ll add this as soon as I can, as I am already working on other navigation stuff like Rinex 4.
OK, I have added the required methods in branch issue-1047, so there’s no need to file a bug report.
Please be aware that there are still bugs there, see comments in issue 1047.
Concerning omega, it is there under a different name: pa for Perigee Argument (as there is another parameter named omega for right ascension of ascending node, the name was changed in the API).