At least it works! Thank you very much for your advice.
The solution is here:
generate password with slappasswd
$slappasswd -h {MD5} -s alamakota
so we have:
{MD5}SapmhDOAw3fpOxmLlm62mQ==
and paste it 'as is' to attribute userPassword
then pam_ldap works and I can BIND to database with
the 'alamakota' password. :)
Thanks,
Marcin