You’ve deployed RPC over HTTP/s as per “How can I configure RPC over HTTP/S on Exchange 2003 (single server scenario)? ” document and when you test the functionality of both OWA and RPC using internet Explorer (https://webmail.yourdomain.co.za/exchange) and (https://webmail.yourdomain.co.za/rpc/rpcproxy.dll) it works. However, when you test the RPC connectivity on outlook 2003/2007 the status remains disconnected.
Open up outlook – Tools – Accounting Settings – Change – More Settings – Connection
Select Basic Authentication – Under Proxy Authentication Settings