This has been driving me nuts! I must get into the habit of checking the forums - I thought it was just me but I also notice that the menu on this site is broken in IE6
Thus far I can get the arrows to appear by editing the line (around 200) in style.css which reads
li.AspNet-Menu-WithChildren > a
remove the > so it reads
li.AspNet-Menu-WithChildren a
This apears to work until I looked carefully - it is putting arrows on all sub menu items.
I want to upgrade a site with the new mojo version but cannot until i can resolve this issue. I will keep chipping away at it but my css is not very good.