Hi P,
There shouldn't be any rastering with the method I described. It sounds to me you're either importing your files incorrectly, missed a step, or you are trying to change the fill and/or outline color of the objects you imported to storyline and realizing you just can't outside of rectangles (inability to change color was also explained in my intro/disclaimer in case you missed it). Understand that SL2 places all imported images into a rectangular bounding box. Although you may have imported a vector-like image into storyline, you are only able to make actual edits to that bounding box.
Without further details of the problems you're having, I don't know how else to respond. I would like to help but you're going to need to narrow it down a bit.