I just posted a message to that thread that might help a little bit. I moved (not copied) the roster from my XBox hard drive to a USB flash so there weren't any conflicts when I eventually put the updated file back on my XBox hard drive. I did indeed use the generic DB editor to make the changes using DPyro's NHL 14 config XML file. The generic editor will let you create your own config file, but all the table and field names are EA Sports gibberish. The upside is, if you can figure out what the fields stand for, you can edit way more. I haven't done any of this yet. I just wanted to see if it was even possible to make a simple change that would actually load properly on the console.

Like I said in my post to the thread, I want to create a more detailed guide with screenshots, but I sadly won't be able to do it tonight due to time constraints.