You can use a feather weight knit iron on stabilizer, however, you would have to be very careful as to how you apply it. Since the garment is a knit, an iron on is going to affect the drape. First you would want to make sure the knit of the stabilizer is going in the same direction as the knit of the sweater. Then, rather than cutting a single piece to cover the entire area, I would cut pieces that are just slightly bigger than the individual motifs. I really would hesitate on this and probably just get a pretty camisole instead.