How do I enable QDBM dba handler for windows?

I am running PHP 5.0.3 and Apache/2.0.53(Win32) on WinXP Pro. I have enabled the DBA extention (php_dba.dll) in php.ini. I have downloaded qdbm-1.8.21-win32 and copied the required dlls into the PHP directory (and C:\WINDOWS to be doubly sure they are in the path). How do I enable the QDBM as a supported dba handler? There doesn't seem to be any php.ini settings for DBA, and yes I did restart Apache. There must be a simple or obvious step I am missing. Is there suppose to be another extension I need to download/add to the php.ini file or setting? I noticed someone asked a similar question in January, though not QDBM specifically, but no-one has responded, or the solution wasn't posted. Thanks, Justin Tan