positioning of submenus in relation to parent

I'm using the vertical YUI menu

I want to position the sub menus so they are aligned with the top of the parent in the menu structure is this possible using css?

So instead of;

|
|
| |>

I want

| |
| |>

My reasoning is that my menu some times disappears underneath my main body content (I use a ddblock which uses jQuery to display content)

I've also tried setting the z-index to a higher value for the menu but doesn't do it for me...