Object to XML type conversion?

I am using HTTPService for communication with php script which reads remote xml file and returns it to Flash. HTTPService in Flash recieves the file as Object type so i can’t use E4X to parse it. I can set

HTTPService.resultFormat="e4x" 

but i would like to know how can i in general convert that Object type to XML type without using that built in property? Because there are some occasions when i am not using HTTPService so that property isn’t available.

thanks in advance