[XeTeX] XeLaTeX + Beamer

[Pavel Straňák]

I am sorry if my question is trivial, I am rather a beginner with 
(Xe)LaTeX.

I have tried to use XeLaTeX with "beamer" to create some pretty 
presentation.
It basically works, I can set the font with 'fontspec' etc.
Unfortunatelly all objects filled with colour gradients and objects 
with soft shadows disappear. Also the graphics (e.g. bullets or 
university logo (in pdf)) do not appear.

Is there any way I can improve this behavoir?
Does "Beamer" use some PdfTeX specials that XeTeX can't handle?

What better way would you recomand for creating presentations in 
XeLaTeX?