There is no "Submit" command. How do you know it is waking up the little php script?
edit: Are you using something like this to read the response?
client.println("POST /mypage.php HTTP/1.0\r\n\r\ntestone=1&testtwo=2");
while(client.connected()) {
while(client.available()) {
char c = client.read();
Serial.write(c);
}
}
client.stop();
If you want an exact answer, then maybe you should post your code.