According to this post on the Web, the Direct TV code are the same across all units. [Link: forums.att.com]
The RC73 is a remote that can be configured for either IR or RF.
Not sure if the info below will work but is worth a try.
You might want to try the HR24 file from here.[Link: files.remotecentral.com]
You will need either ProntoEdit or TouchScreenSetup to open this file or perhaps you have some other CCF viewer that might let you extract the codes. I found this note on Wikipedia about a tool named CCFExtractor that seems to fit the bill of what you need.[Link: etcwiki.org]
Also, have a look here and you will find 2 sets of discrete power codes. If either of these 2 sets works, you can look for pronto configurations of the same model (for example H23) and likely be able to use those codes.[Link: files.remotecentral.com]