Elmah add message to error logged through call to Raise(e)

I'm a bit confused at how to add a message to an error logged programatically with ELMAH.

eg:

public ActionResult DoSomething(int id)
{
    try { ... }

    catch (Exception e)
    {
        // I want to include the 'id' param value here, and maybe some
        // other stuff, but how?
        ErrorSignal.FromCurrentContext().Raise(e);
    }
}

It seems all Elmah can do is log the raw exception, how can I also log my own debug info?