Nested UL's inherit their parent's id & class

Hi everyone,

Consider this UL:

<ul id="my-id" class="my-class">
    <li>item1</li>
    <li>item2</li>
    <li>item3</li>
</ul>    

I want to change the last LI item into a nested UL for the second LI like this:

<ul id="my-id" class="my-class">
    <li>item1</li>
    <li>
        item2
        <ul id="my-id" class="my-class">
            <li>item3</li>
        </ul>
    </li>
</ul> 

As you can see, this causes the nested UL to inherit the id & class of its parent, which is not desired behavior. Is this a known problem? Is there a way to work around this?

Thanks