How to publish SharePoint 2010 site with Forefront TMG

Hi,

I'm looking for some information on how to go about publishing SharePoint 2010 with Forefront TMG.

Here's my current set up -

1. intranet.domainname.com port forwarded to internal IP address of TMG 192.168.1.5
2. Single SharePoint 2010 web application in IIS with bindings intranet.domainname.com
3. Alternate access mappings set up in SP - intranet.domainname.com and Front end Server name

I'm trying to configure Forefront TMG to allow me to access the SharePoint web site externally using the intranet.domainname.com address.

I'm trying to set it up so I can use the default Forefront TMG login page to authenticate users in active directory.

I've tried setting up publishing rules in TMG and set up a listener but I cannot seem to get the login page to appear.

Could anyone point me in the right direction of how to properly configure SharePoint with a TMG using publishing rules? I really need this to be working and have exhausted the Google searching on how to do this!

Thanks in advance