Please tell me how the file is created .php-fcgi-starter in /var/www/php-fcgi-scripts/[some_user]/ ? I now that in /usr/local/ispconfig/server/conf/ there is php-fcgi-starter master template. I need to do so created another file with a similar content to a different compiled version of PHP. Both versions of PHP I'm using a fcgi. Sorry for my bad english...
Support for multiple php versions is already available in the ispconfig svn version. You might want to check that out.