HTTP_RAW_POST_DATA

Hi, Could anyone help me with altering PHP sources? Or tell me please where may I ask this question? The problem is when PHP handles a POST request of a known Content-type (e.g. x-www-form-urlencoded), it leaves $HTTP_RAW_POST_DATA blank. I need to alter the sources so that PHP would always put the request data into this variable. This would allow me to handle malformed POST requests. For example, if a client sends a request of Content-type x-www-form-urlencoded and the data is NOT really "urlencoded", such request seems to get lost. I can't find the data neither in $HTTP_RAW_POST_DATA, nor in $HTTP_POST_VARS. I figured it would be great if PHP could always set $HTTP_RAW_POST_DATA independently of the Content-type.