That’s not true. Award classes are shown for flights that appear in the search results using their native flight numbers. They are not shown for codeshares because the award buckets don’t exist in codeshare inventory. So, if your search results show LH1234, it (should) have X, I, and O (if applicable) buckets; if they show UA7234, operated by LH, it won’t.

Expert mode is of limited utility when it comes to award searches, however, now that UA has removed the ability to construct your own award by piecing together flights with availability. Since the new system only allows you to book flights if they appear on a search from your origin to your destination, just do that.

If you really want to see award inventory buckets, consider an ExpertFlyer subscription at $10/month. The search results there won’t show I2 — they just show yes/no depending on the number you request — but you can set up an alert to be notified if availability appears. ExpertFlyer doesn’t have access to IN inventory, but IN > I is extremely rare anyway.

Also, don’t forget that with Chase points, you have other program options as well. KrisFlyer (from Singapore Airlines) is worth a look if you don’t mind adding a connection; you may be able to find inventory on JFK-FRA or IAH-MAN that connects to Africa. Also, you have access to British Airways (but beware — they charge for fuel surcharges), Air France, Virgin Atlantic, and Korean Air (SkyTeam / Delta partner). I’m not sure which of the programs besides BA charges the fuel surcharge, but anyway it’s worth considering.