First use the LEARN function of the remote (in the Tools menu) and TRY each possible code-set to find those which have the basic Power-on/Power-off functionality that you need. (Not much point in TRYing other buttons because most of them don't have IR codes associated with them in the as-shipped remote!)

Now use PENG as follows:
Pick Add IR Code for any old button, pick the Device Type and Brand for what you're interested in. Then momentarily select the code sets that LEARN indicated were candidates. (My experience is that they're in the same order in the drop-down list as they were in the 3000.) See which of the possible candidates have most of the functions your OEM remote has. Create a virtual remote (with all of the buttons from your OEM remote) and try the candidate code-sets to see which gets you closest. You'll still have to teach the 3000 some codes.
Barry