Authenticating via RPC over HTTP(s) on single/stand-alone Exchange 2003 server

I'm in the process of finalizing the setup of our new/only Exchange 2003 server.  Almost everything (i.e. Exchange/Outlook, OWA, OMA, Exchange Active-Synch) is working perfectly.  The one thing that is NOT working is RPC over HTTP.  It looks like it's setup properly.  I've seen many guides on this and I've done everything that Microsoft, Petri, and MSExchange.org have said.  I ran the rpcnofrontend.exe program.  It all seems pretty straight-forward.  The problem that I have is that I cannot authenticate.  Outlook prompts for login credentials.  After I input my username and password, it just bounces back asking for credentials again.  Every combination of username and password has been tried.  I've tried the web browser 'test' by going to http://servername/rpc.  Nope.  First I tried this whole setup without anything fancy (no SSL, Basic Authentication).  I just wanted to see it work first.  Then, in my reading, I saw passages like "If you use Basic Authentication, you must use SSL."  Was that just a strong suggestion or a real fact?  I ran the Exchange Best Practices Analyzer, but it didn't show me anything related to authentication or security issues.  I got someone who knows more about this than me to help out with creating a certificate on the server.  We setup SSL on the whole Default Web Site.  OWA seemed to respond to that change, but still worked once I provided the httpS:  Exchange Active-Synch broke.  My PDA (Dell Axim, WM5) said the certificate was invalid.  I couldn't figure out how to get around that even though the browser (PC and PDA) seemed to be able to do that.  I don't know if this is relavent or not, but I posted this in a previous question that I've not gotten much response from...  I installed POP and IMAP (to support Blackberries and iPhones).  I can't authenticate to those protocols either.  I've telnet'ed to their ports (110 for example) and tried to login with USER and PASS credentials.  All I get is an -ERR. Login failure.  Unknown username or bad password.  This is really starting to drive me crazy.  My boss is riding my back to get this resolved.  He's even offered me a $100 shopping spree if I can get it fixed before the weekend.  He's really anxious to get this going so he can use the Outlook client instead of OWA.  Please, please, please... Somebody help me out here.  Throw me a bone!!  Thanks for anything...