Where to set extended XML handling in WESOUT while sending XML

Hello Experts,

Requirement : Add a Z field to a standard message type so that

it can be sent to another system while XML .

Transaction cod e: WESOUT is used for that.

But as per the link :

http://help.sap.com/saphelp_nw04/helpdata/en/73/3f5c3c3906b006e10000000a11402f/content.htm

SET_EXTENDED_XML_HANDLING should be set.

I agree that it should be done via framework it self.But can any one suggest a possible place where we can make

frame work to consider the handling of extended structure.

Thanks

~Raj