There are a number of ways to backup wimax keys, but they all require root. If you've already got root, as frenchy said, just make a nandroid backup (RA 2.2.1 will require you to select the wimax partition when making the backup). If you haven't already got root, the best you can do is follow the first part of this method (or the whole thing) first:
[ROOT][GUIDE] HBoot 2.02/2.10 SOFF - There Will Be Root - Upd. 01.26.11 - xda-developers
Basically, you get temp root, then make your backup manually. Your best bet at this point is to just make a nandroid backup.
[ROOT][GUIDE] HBoot 2.02/2.10 SOFF - There Will Be Root - Upd. 01.26.11 - xda-developers
Basically, you get temp root, then make your backup manually. Your best bet at this point is to just make a nandroid backup.