EDI: Syntax error in IDoc (segment cannot be identified)

Hi,

We added custom segments to an IDoc and we can see that Idoc segments are correctly populated. However, at we02 we can see that idoc structure isn't ok, and it retrieves the following sintax error:

EDI: Syntax error in IDoc (segment cannot be identified)

Do you guys know where could be the problem?

Thanks,

Luí