Ouut brightness VGA adapter MBA 11.6

Using my new 11.6 MBA for presentations.

I have the VGA adapter connected to the projector, the same projector I have been using with Mt white MacBook, with the adapter for the white MacBook.

I am using Keynote as my presentation program.

I have the new MBA VGA adapter.

The output is much dimmer for the same slides using the MBA than the WMB (White MacBook).

I tried just adjusting the screen brightness and it did not seem to make a difference.

Question: is there a way to adjust the VGA brightness?

I tried setting up the display to mirrored or display presentation on alternate display, and no difference.

Thanks,

Andy

I went to see a Mac Genius last night and after much chin scratching and fiddling he came across Apple discussion posting, seems to be at least a partial solution.

http://discussions.apple.com/thread.jspa?threadID=2489651&tstart=30

This seems to be a problem introduced with 10,6.3 or 10.6.4

Andy