wpa_passphrase character woes

[Jan]

hi everybody,

yesterday i had some fun with wpa_passphrase, realizing very late that
characters that are allowed by windows (the plattform the owner of the
net uses) aren't necessarily allowed within wpa_passphrase/linux/bash...
(in my case wpa_passphrase generated the same passphrases for two keys
like "5h7suK$f-Br_F-" and "5h7suK-Br_F-").

So my question basically is which characters are allowed within wpakeys
and why i experience this strange behaviour. wpa-supplicant version is
0.4.5-0 (as packaged by ubuntu).

regards
jan