Answer
The IBM InterJet Mail Server runs is embedded into the Interjet Server. There is no method of running any non embedded software on the Interjet Server therefore it is not possible to provide a porting tool for it.
As far as we are aware there is also no method of exporting the user information from the Interjet server, if there is the user information can be imported directly into GMS via the Users > Add User page.
Keywords:porting, IBM, Interjet, users