Custom CSS bullet list style not showing in IE6

I am trying to use CSS2 to create a simple navigation list of links using a
<ul> tag with a custom style defined containing a graphical bullet.

In the link below, the bullets do not appear in IE6 but do appear in
Netscape 6.2. Is there a way of overcoming this?

I am also trying to center the list in the left column and have had great
difficulty doing so.

In the past I had used a table for this but would like to move away from too many nested tables.

Please visit:

http://www.test.customerdemo.com/xx-list-problem.htm

I have validated the CSS style sheet.

Thanks

Vince