Problems, with reply o resend from a request existing in SDP to another system requests..

Sometimes we send from a request in SDP, to another of ticket system from other company, and this system does not process them ... (eg. Spirit), but sometimes is processed without problems..

We see that Spirit also uses the same format in the subject (##$numberOfSpirit##), and we believe, but it's still a theory ... that Spirit, if it receives our message, with our ticket number in the same format (##numberOfSDP ##) ... and this tkt exists In his system, he hangs on his tkt thinking that it is a new response against his tkt.

And when it does not exist in his system, then it creates and responds with its autoreply.

Do you know this problem or similar?

It is possible to use in SDP instead of ## ... ## other value such as @@ ... @@?

This way maybe Spirit no longer identifies it with a own tkt and creates it again ...

Do you know another solution

Thanks for your help.