Pretty sure that's not the Akrapovic model for the R7.
It'll be either S-Y7R12-APT (the race/track model) or S-Y7R11-HAPT(the road legal version).
Assuming you have the S-Y7R12-APT there is a screw and a star washer to remove to take out the insert. Be careful not to drop those down the pipe.
From the parts diagram it doesn't look like the S-Y7R11-HAPT has a removable insert.
It'll be either S-Y7R12-APT (the race/track model) or S-Y7R11-HAPT(the road legal version).
Assuming you have the S-Y7R12-APT there is a screw and a star washer to remove to take out the insert. Be careful not to drop those down the pipe.
From the parts diagram it doesn't look like the S-Y7R11-HAPT has a removable insert.