extensions when using PHP as MODULE on Apache 1.3.12 (Win32)

I have downloaded mod_php4.dll and started Apache1.3.12. (on Win2000) and it works. But: I don't know how to enable informix libraray! When working as CGI I would add a line in my php.ini: extension = php_ifx.dll but when it's working as module, this doesn't work. phpinfo() keeps reporting same libraries whatever i do with extensions statements in my php.ini file. Does this mean that I have to download source for mod_php4.dll and compile it with some option to include informix (or any other library that i want)? If so, where can I get I what do I do? Thanks Igor