It's been ages since I messed around with it, but if IIRC, it can't be the same account both logged in to the machine and being used for the credentials for remote access. So you can't have account X being logged in on the raid machine and also account X being used for the credentials to access the share remotely.
So you'd need a second local account with password on the raid machine, share the drives, make sure that the new local account is an allowed user, log that account out and then use those credentials to access the share remotely.
Could be wrong, but I'm sure I had a similar issue once and that was the issue.
Easiest no hassle way, as long as there is no one else on your local network that you don't want to have access to the files, is to just turn password protected sharing off. Only other issue with that is if your network gets compromised, then there's no stopping those files being accessed, but then you probably have bigger issues to worry about if randoms are getting on it.
I don't know why MS make it so much hassle with having to have user accounts and permissions and other bollocks set up. Just give me an option for a global share password. You have it, you can access the shares on any account, no hassle and still a bit of security.