Use bitmap as a colour With Code?

Hey there.
Been awhile for a flash as2 question, but came upon a new one today.
I am creating a little drawing app for an online contest using lineStyle and moveTo with a selected colour controlled by the hex values eg 0x000000.

Nothing unusual there, but I was then asked if I could make one of the colours with a glitter. As it doesn’t need to be animated I was hoping there was a way to reference an image to paint with.

Is this possible with AS alone? I know I can easily set the fill colour to an image when working within the fla but never attempted to reference via a swf before with AS.

Would this be achievable via the BitmapData class?
Or should I add the image as a background to the clip and use the brush as a mask?

Any advice would be greatly appreciated.
Cheers