Transparent CCRenderTexture


I have a quick question. I’ve been able to create a screenshot and create a ccsprite from the screenshot as well as save it to the phone’s gallery. But I cant seem to make the background transparent. I’ve tried the beginwthiclear option and setting the opacity to 0 but it still does not work. Does anyone know how I can achieve a CCRenderTexture that has a transparent background and save the image with a transparent background? Thanks in advance.