pattern brush as bitmap?

Hi,

In this photo here, there is a shape filled with a repeating bitmap (stones image)

And the green "grass" is one pen tool line using a custom vector pattern brush.

Is there any way to make the pattern brush be repeating bitmap fills instead of repeating vector shapes?

The repeating bitmap fill (stones image) will perform very well on AIR mobile in GPU mode, even if the pattern is small and repeated many times, as it is simply a repeated bitmap fill.

The Pattern brush however (green grass) is a vector, and becomes heavier on performance depending on how complex.

thanks

edit: so another way to say it is, this photo has a stones image object repeated 10 times. it also has a grass vector object repeated 10 times. I want the grass, along with its auto warped "mesh" following a line to be rendered as bitmap with 1 source