how to config a PHP5-cgi under Plesk 8

HI all,

i tryed hard myself over 5 days, but i missed up,
and google wasn't helping very much.

What i've to do is very strang.
i got a new vHost by 1blu.

It has Apache 2 - php 4.4.2 and Plesk 8 on it.

I need PHP5, so i did donwload it and compiled it as CGI
I think that works, but I don't know realy.

Now to my problem:
I've to config it in the Plesk config files for Apache2,
but i've no idea where to search for these files.
i even don't know how to tell the Plesk version of Apache
that all .php have togo to the CGI-Version of this server.

I hope you can help me out.
Thank you :)

Siegurt Skoda