I'm so glad I found your instructions!
I got an Aastra 390 at a thrift store and I like the phone, but I was not impressed when I saw the idle screen, and even less impressed with the number the softkey dialed - it was an adult chat line. I guess a lot happens 6-7 years after the phone is manufactured :P
So needless to say, I'm glad I was able to reset it, I was thinking if there were ever kids around, I would have to hide the phone from them.
I had found Aastra instructions about how to program the phone online, (eg. idle screen mesasge, softkeys, a bunch of other features) http://adsi.aastra.com/dealer/simple_instructions.htm
and the programming would get transferred via a phone call afterwards, but I wasn't sure if my phone would be screwed up or fixed, the "readme" page had a warning about which serial numbers of phones that could be programmed, and mine didn't have the right info on its label.
It stores a bunch of numbers and has call display, so I'm happy with that, without being able to program the softkeys. A nice feature is that if the number is stored in the phone's memory, when that person calls, their name comes up, no matter what the call display name comes up as (if a name comes up at all). I put all the repeat offender telemarketers' numbers into the phone too.