Hello Robson,
IAR debugger Eclipse plug-in will be supported by the new project wizard in S32 Design Studio for ARM v1.3 which should be released by the end of this November.
- First, you have to install IAR Embedded Workbench for ARM on your machine. You can start with Evaluation version of IAR Embedded Workbench
- Then install the IAR plug-in manager: IAR Embedded Workbench for Eclipse
- Finally install the ARM target plug-in:


when the plug-in is installed restart S32 Design Studio and the new project wizard should offer IAR build tools and IAR debugger options:


Now if you build the project and go to the available debug configurations you can see IAR C-SPY config:

and it offers following devices (I-Jet is supported) :

Debugger session running directly on eclipse has some additional features in contrast to e.g. Pemicro/Segger GDB:

FYI: will publish the release announcement on the community so you should get notified as soon as it is officially released.
Regards,
Stan