OWA rule in TMG ( exchange and public directory failed)

Created publishing rule in TMG for OWA to internal Exchange Server. Authentication is BASIC in Rule and on CAS.

When I test the rule, the following passes:

•  https://webmail.mydomain.com:443/OWA/
• https://webmail.mydomain.com:443/ecp/

HOWEVER - the following fail:

• https://webmail.mydomain.com:443/Exchange
• https://webmail.mydomain.com:443/Public

Not sure how to go about trouble shooting this. please help.