I am wondering if there is any work-arounds using javascript or whatever to get IE to show border-radius or gradient background?
I came across this by looking for fixes to using 'gradients and border-radius' in IE9. And yes while its true you can now use both in IE9, you sadly cannot use them together.
The issue is documented in a a few places:
The issue seems to be related to border-radius not playing nice with IE's old filter gradients. Sadly the release of IE9 did not bring proper CSS gradients.