What character is it in your password giving you the problem? And out of curiosity, do you have a Linux system around to see if it's a Samba or OS X issue?

As far as reporting it to Apple, they accept, but don't respond to all feedback from the public via this page. I've also had success on reporting bugs on their developer mailing threads, and had an engineer work with me on an X11 crash back in the 10.2 days.

Oh, and if your trying to do command line mounts to mount the disk automatically on login, I've found the easiest way is to just connect to the share in in Finder, then drag the disk to the Login Items under the User System Preferences.