Synopsis: Redirect / http://wsrv.clas.virginia.edu/ results in loss of CGI variable content
State-Changed-From-To: open-closed State-Changed-By: brian State-Changed-When: Mon Jul 28 19:45:46 PDT 1997 State-Changed-Why: I found this in the HTTP 1.0 protocol spec, RFC1945: Note: When automatically redirecting a POST request after receiving a 302 status code, some existing user agents will erroneously change it into a GET request.] I'm not sure which UAs they were referring to, but I bet this is the cause of your problem. At any rate, there's nothing Apache could do to cause your browser to not POST data. Thanks for the report.
