Hi,
you could try to modify the email template first, based on which the email with new password is generated (Site Manager - Development - Email templates -
Membership - Forgotten password)You could add instruction here, tell users that the password is case sensitive and add a list of "lost" characters, so they could be able copy/paste them.
Do you think that they would be able to log in this way?
If you really decide to modify the password generation, please take a look at following
forum post.
Best regards,
Ivana Tomanickova