IE RGBa Workaround
For RGBa? in IE, just use the gradient filter with the same start and end colours. The first hex pair is the alpha value (ie: AARRGGBB).
.tools {
filter: progid:DXImageTransform.Microsoft.gradient(
startColorstr=#4D000000, endColorstr=#4D000000);
}
From http://stuffandnonsense.co.uk/blog/about/what_does_browser_testing_mean_today/
last updated november 2010