[TYPO3] totally transparent background in gifbuilder

[Tomasz Trznadel]

hello
is it possible to make transparent background instead of background with a 
color.
i have something like this:
lib.rotated = IMAGE
lib.rotated.file = GIFBUILDER
lib.rotated.file {
  XY = 160,120
  transparentBackground = 1
  transparentColor.closest = 1
  transparentColor = #0000ff
  10 = IMAGE
  10.file = fileadmin/templates/new2.png
  20 = EFFECT
  20.value = rotate=5
}
maybe some mask will fix the problem? i have an image in the background and 
color of gif back gives me nothing i need good transparent.