PHP5 strange problem

[primoco]

Hi, i have installed php5 on the plesk7.6 for windows maintaining the old php4, if i do phpinfo() it show the php4 use php.ini in plesk folder and php5 that is installed in c:\php5 use php.ini in c:\windows\ i enable it as isapi on a single domain manually via iis but now plesk see only php5 and when i create a new domain it come setup with php5 and not php4.
What i need is that plesk continue to setup domain with php4 and when i need of php5 i set it manually.
Any idea on why plesk see php5 that is into an external folder?