Expected result:
1)Postman call to iFlow 
2)iFlow return "Hello <name>, <greeting>"
<name> from constant header and <greeting> from constant property

How:
1)Add first content modifier, set constant header and property
2)Add second content modifier, at body read header and property using camel expression

Package name    : Hello
Iflow name      : Say hello using constant header property and expression body
Sender http path: /say_hello_using_constant_header_property_and_expression_body