SSL reverse proxy using certificates to IIS server

Has anyone gotten an Apache 2.0.43 SSL reverse proxy working to an IIS
backend server requiring certificate verification on the IIS server
side? I can reverse proxy Apache to an SSL Unix server and an SSL IIS
server (neither requiring certificates). I can also reverse proxy
Apache to an SSL Unix server requiring certificate verification. I
have not been able to get it working to an IIS server requiring
certificate verification. I have verified that the Apache
certificates are valid using openssl to retrieve web pages from the
IIS server:

openssl s_client -connect IIS-server:443 -cert user.crt -key
user.key -CAfile ca-bundle.crt
GET / HTTP/1.0



Originally when I tried the reverse proxy to the IIS server I would
get a segmentation fault in ssl_engine_kernel.c. For some reason
info->x_pkey was a NULL pointer. I modified the code shown below to
get around this:

$ diff ssl_engine_kernel.c{.ORIG,}
1606,1607c1606,1609
< *pkey = info->x_pkey->dec_pkey; \
< EVP_PKEY_reference_inc(*pkey)
---
> if (info->x_pkey != 0) { \
> *pkey = info->x_pkey->dec_pkey; \
> EVP_PKEY_reference_inc(*pkey); \
> }

Now when I use openssl to connect to the reverse proxy I get:

HTTP/1.1 502 Proxy Error
Date: Wed, 23 Oct 2002 01:00:39 GMT
Server: Apache/2.0.43 (Unix) mod_ssl/2.0.43 OpenSSL/0.9.6g DAV/2
Content-Length: 453
Connection: close
Content-Type: text/html; charset=iso-8859-1

Proxy Error

The proxy server received an invalid
response from an upstream server.

The proxy server could not handle the request href="/">GET /.

Reason: Error reading from remote server