Accessing OWA through ISA

Our users always have problems accessing our OWA server when they are on remote sites protected by ISA firewalls. They will be repeatedly asked for their name/password. After several attempts they will get a “login failed” message and be left witha partially completed OWA page in their IE browser. This only happens with IE version 5 or above. If we use Opera or Netscape we don’t get the problem, but the user then doesn’t get the full OWA2000 interface.

Help!