Then you only need use c_move with a value for the rel_dist or rel_vel - don't remember the names now.

I didn't know that you use the physics for the movement, that makes it a bit different.
You probably have to add forces parallel to the wanted axis, instead of using c_move - I don't have any experiences with the physics engine.

Looking at your code:
- Why do you make it related to the camera's angle while speaking about x axis and y axis?
- And, you shouldn't put any while instruction into an event, you should use the event only for changing any values, for instance, a flag that activates and de-activates the entity's movement or such.