Is SSLProxyMachineCertificateFile read in at start or usage?

(I have sent a copy to the users.DeleteThis@httpd.apache.org mailing list, but
not got any reply)

- Im using Apache 2.2.4 with mod_so compiled in -

When is the file specified in SSLProxyMachineCertificateFile
being read in? At apache start, or when it needs a certificate in that
file?

The reason of Im asking this, is because Im setting up a Apache SSL
proxy, to be able to virus
scan SSL traffic.

But some bank sites require client validation, so Im have decied to
make use of templates so the
user is presented with a link to a CGI upload page, when the user
visit a page for which apache dosent
have client certificate for. (In other word, when authentication to a
site fails)

Then this CGI script will load in the SSLProxyMachineCertificateFile
PEM file, PEM-encode all uploaded certificates, add them
to the PEM file, and then write that file directly to
the file specified in SSLProxyMachineCertificateFile.

And here rises the problem.... Is the SSLProxyMachineCertificateFile
file read in at start, or at
each request that requires SSL client certificate....
(If the file is loaded at startup, any changes to that file will not
have any effect until next restart)

And if that file is being read in at certain events, is it then
possibly to force reload of the
SSLProxyMachineCertificateFile file by sending some signal to apache,
without restarting apache?

No, im not allowing them to change the CONFIGURATION...
Its the PEM files that the configuration refers to that the user will
be able to append to, but not delete, change or read.

The user will be able to append her own client certificate.

The CGI will simply contain a list of CNs, and validity dates, of the
certificates currently in the system, and then contain a file upload
box, and a box for entering private key password.

The user will simply select his/her certificate from his/her system,
enter the private key password in the box, and then the CGI will
decrypt his client certificate and append it in the PEM file specified
by SSLProxyMachineCertificateFile, or in the path specified by
SSLProxyMachineCertificatePath .

But SSLProxyMachineCertificatePath (Not the
SSLProxyMachineCertificateFile), is certificates in that folder read
in when a certificate from that path is required, or is this path
readed in and cached at startup like the
SSLProxyMachineCertificateFile?

Or is there's any way to force apache to reload the
SSLProxyMachineCertificateFile/SSLProxyMachineCertificatePath without
restarting apache. (I mean, I dont want all new connections, and
current connections to fail, when a user uploads a client certificate,
even if I reload apache gracefully, when it restarts, new connections
will fail for a little while)