IntelliGantt Web Part for SharePoint 2010 Sandbox

SharePoint 2010 introduces a 'Sandbox' mode that limits the scope of what a web part is able to do on the server. This is something of a curious feature for a Sliverlight-based web part such as the IntelliGantt Web Part because it doesn't do anything on the server-- it's only downloaded from the server and then runs on the client. In fact, here is the source code in its entirety for the IntelliGantt Web Part when built for sandbox mode:

public class IntelliGanttWebPartInstance : WebPart
{
protected override void CreateChildControls()
{
base.CreateChildControls();
}
}

That's it. The only difference between the IntelliGantt Web Part in sandbox mode and the 'normal' IntelliGantt Web Part is the latter is able to plug into the web part editor forms to make it easy to configure all the IntelliGantt Web Part options. In sandbox mode, you'll have to supply all the options yourself in the 'Custom Initialization Parameters' field.

However, we realize that sometimes policy will dicate that the IntelliGantt Web Part is deployed to the SharePoint 2010 sandbox. Here's how to do it.