Hohn,
"One For All" type remotes use "lookup" table matrices to create codes for various remotes. These table provide IR carrier frequency, as well as specific data streams so the remote can create the IR code to be emitted. The "magic" function on these remotes provide access to functions that are not "on" the buttons on the "One For All" remote face. If a mfr supports elplicit codes, then you may be able to find them in this way. Many(most) mfr's don't support explicit codes. If for example your reveiver remote has specific source select codes, then these codes would likely be in the tables. If it doesn't, then they wouldn't. Companies marketing such remotes actually obtain OEM remotes and "capture" and deconstruct the codes and create table accordingly. I have had a recent experience with sending a remote in for capture and found out that a new "executor" was required to learn some of the codes. This meant considerable time and effort on the remote mfr's part, whether there are one or one million of these products in the consumers hands.
I hope this answers your questions.