yeah, forgotten that i testet at least, to strip the index.php complete and see, if yaws handle it like a normal call to document root (like that calls the same like
but an url like dont call the index.php

I have now handle it with an 404-error module, what executes the index.php as a cgi.

out404(Arg) ->
    out404(Arg, get(gc), get(sc)).
out404(Arg, GC, SC) ->
    yaws_cgi:call_cgi(Arg, GC#gconf.phpexe,  lists:flatten(Arg#arg.docroot) ++ "/index.php").

but iam still interested, if and how i can change the or an other php $_SERVER variable like REQUEST_URI without change the file which is executed and without use the call_cgi, also by the normal method to let yaws handle if this is (for example) an php file.