Either I'm an word not allowed or i'm missing something. In simbrief dispatcher there's an option to 'import flight plan', and then it's imported into FS worldmap, departure and arrival are set for you. However, nothing is imported into the MS EFB flight planner, making it impossible to do 'send to avionics' to populate the Garmin flight plans.

I have even tried to export the flight plan from Simbrief to .pln and load in MSFS, but then same thing.

I need to have the flightplan in simbrief to use BATC. Any way around this?

I made a flightplan in Simbrief yesterday, exported it and loaded it into the EFB (use the Load/Save option at the bottom of the Flightplanner in the EFBn not the one on top).
After that the flightplan with all the waypoints was in the EFB but something got messed up when I used the "send to avionics" option.
It was down in the Garmin alright but only up to first waypoint and then cut-off. No clue why yet though because making a flightplan with the EFB works fine when send to avionics.