Bleutooth Keyboard (re-)pairing issue

I've no problem connecting my bleutooth keyboard to OSX 10.8.4 Mountain Lion!

However, occasionally the OS "lost" the paired device after sleep or reboot and wants me to re-enter the random code to pair it again.

Not only is this frustrating, but the original keyboard is broken and thus can't be used to login to the computer. But the random code

pairing verification only comes up AFTER logging in.

Only way to handle this, is to connect my asus USB keyboard, login to OSX and then I see the question to pair the bleutooth

apple keyboard.

so,

1) How can I make OSX to remember or stick the paired device

2) If OSX is that badly programmed that it can't handle this simple task which can be automated easily under Linux, Unix and Windows

how can I make sure unpaired devices can pair again before logging in to OSX

To avoid cluttering, only respond to this plain direct and simple question if you know the solution to the question. I've used this support communities succesful several times, but sometimes the first 20 answers are just :"I want to know this too" or "don't know." So only answer if you know the answer.