Microsoft recently released a hotfix to resolve an issue where Windows 7 SP1 DirectAccess clients fail to connect to a DirectAccess server with the IP-HTTPS IPv6 transition protocol and using One-Time Password (OTP) authentication via the DirectAccess Connectivity Assistant (DCA) 2.0. In this scenario you may receive an HTTP 403 error from the DirectAccess server in response to the certificate signing requests and a 0x80040001 error after entering the OTP.
You can learn more about the hotfix for DCA 2.0 on Windows 7 SP1 and download the associated hotfix here.