Another tux caveat

Kernel 2.4.25-tux
running Tux 3 userspace
Apache 1.3.29

I have a server where I have tux.mime.types set to redirect .php and
.shtml files.

I have multiple IPs on this machine, tux serves just fine, hands any 404
request to the backend (since index.html is not found) and things are
great.

However, I have one IP address where I don't want to have tux serve due
to the fact that there is content that should be behind http auth
protection.

So, I echo 'http://192.168.24.102:80' > /proc/net/tux/0/listen/0

I start tux, start apache.  with index.html present in the directories
for both .102 and .103, Tux will answer fine on .102, apache answers
fine on .103.

However, when I remove index.html and put index.php there, tux refuses
to pass the request to the backend if it comes in on .102.

If I put 404.html in there, tux will serve that.  Of course, changing
the listen statement back to http://0.0.0.0:80, will allow tux to serve
both 24.102 and 24.103 on port 80 and will properly redirect to the
apache backend.

<VirtualHost 192.168.24.102:80>
  ErrorDocument 404 /index.html
  ServerAdmin [email protected]
  DocumentRoot /var/www/test.com
  ServerName www.test.com
  ServerAlias test.com *.test.com
  CustomLog /var/log/apache/test.com-access.log combined
</VirtualHost>

<VirtualHost 192.168.24.103:80>
  ErrorDocument 404 /index.html
  ServerAdmin [email protected]
  DocumentRoot /var/www/test2.com
  ServerName www.test.com
  ServerAlias test.com *.test.com
  CustomLog /var/log/apache/test.com-access.log combined
</VirtualHost>

Any thoughts as to what I might be doing wrong?