Found the below info from a different SI… This should explain why you see ‘null’ as output.
“The xopObject is shown as null in Developer/Designer since object serialization/de-serialization of XOP objects is currently not supported in IS 8.2 as a whole. This is just an issue of displaying the object in the Developer/Designer tools and does not affect the functionality.
E.g. when exposing the service (with xobObject variable as output) as a web service, IS 8.2 does return a proper non-null value.
So this is not a product bug issue but a current restriction of wM 8.2 implementation.”
HTH
Senthil
#Integration-Server-and-ESB#webMethods