Javascript - Update JQuery DropdownChecklist From Server-side?

I'm working on an ASP.Net webpage which will use the jQuery Dropdown Checklist (http://code.google.com/p/dropdown-check-list/). I'm fairly inexperienced with JavaScript and completely new to jQuery.

Basically, my question is: How do you update the selected items in a jQuery DropdownChecklist from the server-side?

NOTE: For details on the solution, scroll to the bottom of the question.

Here's some background to give you a better idea of what I'm doing...

I have a jQuery DropdownChecklist which is being populated when the page loads. When a user selects an item in the DropdownChecklist, the selected values are collected and stored in a hidden input field, then a postback is performed, which allows the server to update a server control. This part is working.

Now, here's my problem. This server control, which is actually a usercontrol has a "Remove" button for each selected item in the DropdownChecklist. When a "Remove" button is clicked, it should cause the associated item in the jQuery DropdownChecklist to be de-selected. So, far I haven't figured out how to make that happen.

Here's some relevant code snippets:

Here's the markup...

<asp:ScriptManager ID="smScriptMgr" runat="server" />
<table>
<tr>
<td>
<select id="s1" multiple="true" runat="server" />

[Code]....

We determined the simplest solution was to call the JavaScript function from the client-side rather than try to do it from the server-side. The ImageButton does have an onClientClick event, but for some reason it didn't work. However, wrapping the ImageButton in a client-side anchor tag and using its onclick event did the charm.