Configuring ISPConfig with ODBC, Oracle, and such

[Torchwood]

I am currently looking at using ISPConfig 3 to replace a POS IIS server in our environment. This would be a internal-only server hosting internal web apps. This requires that I enable the PHP libraries for ODBC, Oracle, and LDAP for all sites on this server. (MySQL will also be used, however, some other servers that we get info from speak ODBC and Oracle.) I believe that it should be possible, however, where would I edit the files on the web server? Also, would I do this before installing ISPConfig?

The instructions that I am looking at are for the Debian Lenny x64 server, BTW...