There's no way to get your RSA keys back if you don't have a backup. You can't just take it from another phone, they're specific to your device.
If you have a nandroid backup from before you lost them, you may be in luck. If you're using Amon Ra, you should have chosen to backup wimax at some point. I believe CWM backs up wimax with each backup. You can open up your nandroid backup and see if you have a wimax.img file present. You can then restore that backup or manually flash the wimax.img.
Are you 100% positive that you lost them? It's kinda hard to do unless you specifically chose to format your wimax partition.
If you don't have a backup (I'm going to emphasize again the importance of making a backup) and your RSA keys are gone, you're pretty much SOL. You broke it, you should have to buy it.
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