Invalid credentials when attempting to use IMAP SSL with Exchange 2003

Hello,

I'm in the process of enabling IMAP SSL for an external user. I've looked over the documentation and am pretty sure I've followed the correct procedures. This is for a Exchange 2003 SP2 on SBS 2003. In a nutshell, I have done the following:

- Enabled the IMAP service for auto start.
- Tested IMAP (143) successfully from outside.
- Forwarded Port 993 to the server from the firewall.
- Ticked the box in the default virtual IMAP  server to require SSL.
- Applied a self-signed certificate.
- Verified the port numbers for unencrypted and encrypted IMAP traffic under advanced.
--------------------------------------------------
The Error:
Your IMAP command could not be sent to the server, due to non-network errors. This could, for example, indicate a lack of memory on your system.

Configuration:
   Account: DOMAIN(testacct)
   Server: mail.domain.com
   User name: testacct
   Protocol: IMAP
   Port: 993
   Secure(SSL): 1
   Code: 800ccc0f
--------------------------------------------------------------

I've tried establishing a Telnet connection to port 993 but the connection times out. This is both externally and from the localhost. I do have Routing and Remote Access enabled for VPN connectivity and wonder if this might ahve something to do with it. Though I checked for NAT/Basic Firewall under the RaRA settings and it is not an option the is present.