Hi,
XML would be the best way to go.

>Hi
>
>I have a need to share transactions (ie orders) and their dependancies between two (or more) systems. The order gets sent to a system and is returned with alterations & possibly additions.
>
>The systems are such that underlying unique keys in both systems cannot be transfered.
>
>I am interested in peoples views on the best way to go about implementing this.
>
>Regards
>Geoff Scott