How open multi client connection on Sumo using veins_launchd script

Question

I'm working on veins and Sumo and I'd like to know how to modify the veins_launchd script in order to launch a sumo istance with the parameter --num-cliens 2.

I'm referring to this: How to give sumo options with sumo-launchd.py?

and I've tried to use:

./veins_launchd -v -c "sumo-gui --num-clients 2"

but when I press the run button on omnett++, it appears this error:

Error

I also tried to launch the sumo just with the command:

sumo-gui -c <path to my sumocgf> --num-clients 2

and it seems to work until I run the simulation, where an API version problem appears.

I also don't know hoe to set the setOrder command.

Can someone help me? Thanks a lot.