I'm really stumped here. Exprox.dll redirects the /exchange directory on the cas to the 2003 BE server no problems, however if i create/move a user to a 2007 mailbox server the cas server directs to the /exchange directory and gives a 404.3 SSL required (even though it is an HTTPS url and the cert is fine). I tried a custom error on the /exchange directory to do an HTML redirect to /owa, but no luck there either. Any ideas?

Is SSL set to be required the /exchange virtual directory or on the Default Web Site?

it is on both, the default web site has a custom 4.3.4 error to redirect to https://webmail.company.com/exchange the oddes part is, i've done this for another company, so i checked all the IIS settings against eachother and they match...ugh

got it figured out; the mailbox server used to host a CAS role as well, so SSL was set as required on the 07 mailbox servers /exchange dir....DOH and here i was thinking exprox.dll was hosed up! LOL