I've never heard of a good universal remote (basic good, as in something from URC or ProControl) not being able to learn IR codes from another remote. More than likely, an existing IR codes set was used for those remotes, especially if it is a small manufacturer. It could be something as simple as a code set from an old Sony Trinitron tube TV. It wouldn't matter. As long as the receiving IR chipset can "see" and interpret the codes sent from the remote, it would work.
If the remote is RF, (rare, but possible) then that can be a different can of worms. At that point, the OEM remote would be the easiest way to go.