HTTP service in dual stack PI

Hi

We have PI 7.1 dual stack and a sender http scenario.  As we know that http protocol supports transfer of any xml , image / html page etc

1. So if i send any xml / image / etc will it get converted to xml by the http adapter seervice that is part of integration engine  OR do I need to ask the http client to send only xml  ( in the sender data type format )

2. does sender http service allow GET or POST transfer by default ??

hema