About image settings and Vfb

[will_will]

Hello!
We got a problem.

For example:
First render a image, including some mesh and black background.
And run the script code:

/* save bitmap through vfb command */
pngio.setAlpha false 
vfbControl #saveimage "D:\image1.png"

/*copy image to bitamp var and save */
newmap = vrayVFBGetChannelBitmap 1
newmap.filename = "D:\image2.png"
save newmap

The image1 has alpha channel, the image2 hasn't..
Can I use vfbControl command to save a no-alpha png image file , let the image format settings work?
Thanks.