MDS Services is not required for this. MDS Connection Service, which is installed under the base installation, is required to be running and enabled for the user (default behavior). On the device, open up the BlackBerry Browser and type the fully-qualified domain name of the intranet page you want to access. You can further this by adding the default LAN domain name to one of the MDS config files (search for 'domain.com' on here or BlackBerry.com) and then you can simply use the hostname of the intranet site.
You do NOT need MDS Services and all the headaches it brings to you.
Think of MDS as a built-in VPN of sorts for your device. It can be used for any TCP-based application, including the BlackBerry Browser, to traverse back into your internal network over a secure channel.